Frequently Asked Questions
Why a solenoid isn’t digital
There is a common view that a solenoid is either on or off, open or closed. One position or the other. Indeed in many applications this is the case with power supplies being either open or closed and the solenoid being either open or closed. However, there is a whole world of possibilities introduced when one considers the idea that a solenoid is not a digital, but analogue.
What do we mean by digital?
We use digital here as a shorthand expression. What we man in practice is that it not a 0 or a 1 – open or closed – but an analogue wave, with various options available between the two main positions.
2 quadrant solenoid control
If the coil has a spring then it is perfectly possible to use standard 2 quadrant control to very good effect. This will react against the spring and can therefore be used to create an analogue ‘range’ of options from fully open to partially closed to able to hold in a certain position.
A four quadrant solenoid?
If the plunger is free then it is possible to use four quadrant control to create exceptionally accurate control over the way in which the plunger is positioned.
This can be held against light resistance or can be locked if higher pressure is occurring within the system (for example). This can provide huge amounts of control in applications such as flow control applications or related process control projects. Current control can be used to directly tier the solenoid holding power and use the most efficient amount of current for the particular application.
Pulsed solenoid operation
The final option that can be used involves using a solenoid in the same way as normal with the exception that it is controlled in a way that enables switching them on/off quickly. It is quite likely that this will use much less overall power to achieve the same effect, but the flow through the solenoid will have pulsations (high and low pressure) that can damage mechanical components after time.
What is brushless DC motor cogging and how do I get rid of it?
A common issue, especially with sensorless brushless DC motors
‘Cogging’ is a general term (possibly even a colloquial term) used to describe a brushless motor appearing jumpy or jittery. It is much more prevalent at lower speeds than higher as high speeds tend to smooth out the motor considerably. An example of ‘cogging’ can be seen in the video below in the unoptimised brushless motor and controller example.
Note how the motor stutters and jumps at the startup phase – rather like an engine on a cold day without enough choke on. Eventually, as the speed increases, the motor begins to smooth out and the issue is no longer prevalent. However, it can cause numerous potential issues in practice, issues at startup are common as can be seen in the video. This can even lead to entirely unreliable starting in certain cases, where the motor will start 6 times out of 10 and the other 4 it will judder, cog and then not start.
What are the options for eliminating cogging?
There are several potential solutions for reducing or eliminating cogging which are all worth exploring. Some are more relevant to certain applications than others but it is going them.
- Firstly, it has to be noted that sensorless motors are much more likely to have this issue than sensored motors. Therefore, a simple fix may be to look at introducing a sensored version of the same motor rather than a sensorless motor. However, we understand that in a number of applications this may not be possible for technical and / or financial reasons. If this is the case then please read on as there are a number of potential options to reduce cogging with sensorless motors.
- Switching to a brushless motor with more poles – the more poles a motor has the smoother it will perform at lower speeds (where most cogging occurs). This will typically make startup easier and reduce cogging.
- If you are using a sensorless motor then a trapezoidal type controller will have less chance of starting up as required than will other types of controller. We’d suggest you try to use a sinusoidal brushless motor controller – sinusoidal controllers perform better at lower speeds and hence are likely to reduce cogging.
- Check current settings. One common cause of cogging is that the startup current settings are not set appropriately. This is especially true in applications where startup occurs under load. Increasing the power going into the motor at startup can give the motor the ‘extra kick’ that it needs to avoid cogging.
- Use a carefully optimised brushless motor controller. We regularly optimise our brushless motor controllers for a range of customers to help address the challenges of specific applications. As can be seen in the video above, this can lead to a significant benefits and can entirely eliminate cogging from the startup and running of the motor.
How do I know which solution is best for my application?
There are certain solutions which may be completely impractical for your application – whether it be a cost or technical issue. For example, higher pole count motors or sinusoidal controllers typically (though not always) increase the cost of a project. Equally, sensored options are typically more costly than sensorless.
As with many things in motor control engineering, the answer is typically bespoke to you and your project. If you need incredibly smooth startup every time then it is likely that a fully closed loop sensored system will be the best option. However, if you need reliable startup rather than smooth startup it is perfectly possible to optimise a low pole count sensorless brushless DC motor controller to deliver exactly the performance you need.
Solutions such as optimising a trapezoidal brushless DC controller like the ZDBL15 are very low cost and (depending on the required volume we can even carry this out at no cost). This method is highly reliable because it tailors the controller not just to the motor you have but also to the specific demands of the application.
If in doubt – give us a call – we’re happy to help
As mentioned above, finding the right answer to resolving a cogging issue is often application specific. We would always encourage you to have a quick look at our optimised options as these are increasingly popular due to the time and cost savings available by doing it.
However, we do always encourage you to get in touch with us if you are having this issue or would like to discuss the best option for your particular application. You can click here for contact details for us and if you have any questions please ask.
What is power density and how does it affect my choice of motor?
Power density is the amount of power that a given motor can handle per unit volume. In really simple terms we might call it the power to size ratio of a particular motor.
The reason this particular measure is important is also relatively straightforward – namely that, in applications where size (and also weight) are important factors, the power density of a motor is a critical performance measurement. This is because it indicates the relationship between the size of a motor and the power that motor can deliver. In lightweight (often battery powered) applications such as drones or automotive applications, high power density can be hugely important.
OK – so the higher the power density, the better for my application?
Not necessarily no.
There are other factors to be considered when thinking about the right motor for your application. For example, the relationship between speed and torque that you require, do you need reliable positioning or intelligent control in this way?
A typical (though not always the case) feature of many motors with high power density is higher speeds and less torque. This may well mean that you then require additional gearing to get the speed and torque combination required for your project. Adding gearing adds inefficiencies and weight and therefore goes against the power density of the whole package.
Likewise stepper motors offer very poor power density but for certain applications are the only type of motor which can really achieve what needs to be done.
I need the best possible power density I can – what motors should I use?
Almost certainly you will want brushless DC motors. However, the exact type and design of brushless motor you require will depend on the specific application you have. To find out more about the different types of brushless motor and the pros and cons of using each type please click here.
Depending on your application you should also think carefully about whether you opt for sensored or sensorless brushless DC motors as this could also have an impact on the performance options you are able to achieve. There are a large range of potential brushless DC motor controllers available to drive all types of brushless motor but you will need to think about this when designing your product.
Final thoughts: an important consideration but don’t lose sight of other factors at the same time
For certain applications – largely space and weight sensitive applications – power density is undoubtedly a very important factor. However, for other applications it may be less of an issue and other factors may trump the issue of power density as a factor.
Good wiring practice – Things to think about when wiring up a motor controller
Strip the right length of wire
One of the most common problems when wiring in a motor controller is that the user inadvertently strips either too short or too long a length of wire.
Too short and it can become hard to get a good connection in a screw connector (and especially hard if a soldered connection is required). Too long and you run the risk of the cables shorting either on each other, on the driver itself or on something else in the application. Depending on the motor controller that you are using, a short like this could completely blow the controller.
Typically, 5-10mm is a good length but this will vary depending on the type of connector that you are using.
Consult the datasheet or startup guide first!
One of the most important aspects of wiring up components such as motor controllers is wiring things up in the correct order.
Typically this involves connecting all the various outputs to the controller before one connects the power connectors but it is always best to consult the datasheet or user guide first.
A good workman doesn’t blame his tools because he chose to buy good ones and bring the right ones.
Whilst you would never catch any of us blaming our tools, we would also hope that the same goes for you.
Buying good quality tools can make a huge difference in the quality of job you are able to achieve, especially where soldering is required. Getting a nice, clean length of wire is critically important in getting a good, solid connection into the controller. Trying to strip wires with a blunt penknife might not get you where you wish to be.
Hold your nerve!
With fiddly wiring jobs it can be common to get exasperated and try and force the issue.
If you find yourself about to jam a frayed wire into a stripped screw connector or picking up gaffer tape at any point then it’s generally better to put the kettle on and have a think.
Take care to follow the wiring diagram and use different coloured wire where possible
It is always a good idea to use different coloured wires where possible. These will enable you to clearly distinguish wires when connecting them and can help prevent connecting the motor phase wires the wrong way round.
If this is not possible try and use pen or electrical tape to mark the cables individually so you know exactly which ones you’re dealing with.
Can I drive a sensored brushless DC (BLDC) motor with a sensorless brushless DC motor controller?
Sensorless brushless motor controllers can work very well with a sensored BLDC motor
The quick answer is yes, you can, provided that you connect everything up correctly. That said, it is important to be clear about your reasons for doing this.
A sensored brushless motor is a brushless motor with sensors in it. A sensorless brushless motor is exactly the same as a sensored brushless DC motor with the exception that it does not have sensors installed. Many manufacturers make exactly the same motor (in terms of frame size and electrical specifications) but simply offer it in sensored or sensorless variants.
This therefore means that a sensored brushless motor can in essence be treated exactly like a sensorless brushless motor. To do this you must first ensure that the phase connections are wired in correctly but the hall sensors wires are ignored. It is important to remember that, if you do this, the motor that you are using will then become a sensorless motor so any performance characteristics that you were getting if you had been using a sensored brushless motor controller will now be different. However, there is no danger or issue in doing this and it is a (relatively) common option for those wishing to cut costs or where a motor with perfect mechanical specifications may only be available in a sensored option.
Performance characteristics may vary depending on the brushless motor controller
If you are thinking of using this method for a number of reasons then it is important to be aware that there may be particular issues that you need to be aware of. Generally speaking, the most important of these relates to lower speed or startup of the motor which may not (at least initially) be as smooth as it would have been with a sensored motor controller.
Any technical information you may have on the motor which is based on it being run as a sensored motor will also no longer be necessarily accurate – this is especially true at lower speeds. If you are not entirely sure about this or have any questions please give us a call to discuss.
It is worth remembering that there is no obvious reasons to do this in practice with the exception that sourcing motors for specific applications is sometimes difficult and we have had clients in the past who have only been able to find a sensored brushless motor which met the torque/speed requirements their project required. Again, if you have any specific questions here please feel free to give us a call or email.
Customisation is always an option
Depending on the volumes that you are purchasing for your project it is also usually possible to talk directly to the manufacturer in order to get the sensors removed and a discount applied. At volume, it will undoubtedly be possible to save money by removing the sensors from the motor at the manufacturing stage.
It is likely that you will need to setup the sensorless brushless motor controller to deliver the correct drive pattern depending on the specification of the sensored brushless DC motor that you have. It is always important to take into account the number of poles and key electrical characteristics of the motor.
If you have any questions about the best way to setup your brushless motor and controller then please contact us. Our team can even set the controller up for you specifically for the motor that you have.
What range of technical support do you offer?
A range of technical support to get your motor control project moving
We offer a variety of technical support for both our stock range of motor controllers and any customised or bespoke motor controllers that you may purchase.
Our business model is fundamentally built on delivering custom motor controllers which fit the applications you need perfectly and meticulous technical support is a major part of this.
One thing that we won’t ask you to do (at this point anyway!) is to ‘submit a request’ or ‘request a ticket’. Instead if you buy anything off us you’ll be able to contact us direct via email, phone or our online chat service to request additional help or support. If you’ve made the decision to invest in a design project with us then we’ll provide you regular updates on progress and will organise site visits at the appropriate stages of the design process.
We understand that investing in and operating motor controllers can be a big decision for you and that many of the features and possibilities may seem somewhat daunting or confusing. That’s why we do our best to deliver comprehensive technical support. Our company motto – ‘Motor Control Simplified’ encapsulates this philosophy – we want to make the process of using our motor controllers so simple and straightforward for you that you will wish you used them years ago.
Our core aim is to remove all of the stress that can be involved with motor controllers to enable product designers, engineers and other professions to get on with the job that they want. We think our technical support options fit in with that vision.
Motor control support over the phone
Our UK based engineers are available on the phone to talk through any problems that you may have. If you have a project where you are looking for the right solution they are happy to discuss this with you. Alternatively, if you have already purchased a controller from Zikodrive we can assist with setup, performance issues or anything else.
Simply call +44 (0) 333 123 7130 and choose the relevant option for your enquiry. We will then either deal with your issue straight away or make arrangements for a call back if all our technical team are busy at that moment.
Skype or Teamviewer support to make quick, easy modifications or to talk more in depth about your project
If you have purchased a new board and need help setting this up or want to make quick programming changes we can assist with this in a number of ways. One increasingly common option is to arrange a Skype or Teamviewer meeting with our technical team in order to enable them to see your motor setup in action. We can then advise on the best route forward or make real time programme changes (provided you have the equipment setup to do this).
Depending on the controllers that you have we can assist you with making significant firmware changes to them. We have several customers who purchase large volumes of the same hardware but who then install a range of programmes on these controllers in order to customise them for their specific customers. If they have a new customer with new requirements they simply give us a call and we will book a session in to get things up and running
On site support to help get your motor control project moving?
We offer fully insured on site technical support from qualified engineers. We will usually incorporate this into any bespoke design projects that we will do – unless otherwise requested. However, if you are considering purchasing one of our standard range of motor controllers and would like a site visit to assist with setup of these controllers then please contact us and request a visit.
What costs are involved in modifying an existing ‘off the shelf’ stepper motor controller or BLDC Motor Driver?
What costs are involved in modifying an existing ‘off the shelf’ stepper motor controller or BLDC motor driver?
Every motor control project is unique
Perhaps not surprisingly, the costs of modifying an existing stock stepper motor controller or BLDC Motor Driver to turn it into a customised motor controller depend largely on the extent of the modifications that you require.
As a basic guide we would split this cost up into the tooling costs involved in making changes to the board and then the design and testing time required to ensure the motor controller meets the exact specifications you require. A simple modification which requires only a change of connector or something similar will require very little design time. However, the addition of extra features or a reworking of the motor controller into a smaller design will potentially take quite a lot of time and therefore add cost. We will however put together a fully costed proposal before we start so you are clear and what you are getting into.
Tooling costs to get your motor control project off the ground running
Any modifications that are made will require custom made tooling to be made in order to then deliver them as full production units. Typically the cost of this is £1000. Depending on the customised motor controller you are looking for we may be able to achieve what you are looking for with a plugin board which could save you money on this (See below for more information on this). However, any physical changes which are required will inevitably attract these types of costs.
Development time to get your motor control project from concept to success
The development time required to deliver your modifications obviously depends on two main factors. The first of these is the complexity of what you require and how different it is to the standard version of the stepper motor controller or Brushless ESC. To provide a basic idea our charges for this are £25/hr for design and testing time and £50/hr for any on site work that may be required. If it is as simple as adding one or two onboard features to an existing stepper motor controller or BLDC Motor Driver then this may only require 1-
The second major factor is how many projects we are already committed to. As a small firm we have limited technical resources available and if all our team are tied up with projects then we may not be able to start the project immediately. If this is the case we will be very clear about this from the start and will be able to provide you with a date when we can start work. Whilst we understand that this can be frustrating if you are keen to get your project moving as fast as possible, it is always better to be clear at the start rather than making promises we cannot keep.
Please note that we are always more than happy to provide fixed price quotes for changes if preferred.
Please also note that the development times associated with customisations and modifications tend to be much shorter than bespoke design.
Whatever you are looking for or contemplating for your project we would strongly encourage you to get in touch with us via phone, online chat or email to start a conversation about how we may be able to help. Please note approximately 50% of our work is based on bespoke and custom design and as we almost always retain the IP of these designs we may have something in our library that is very close to what you require and can be quickly modified.
What about optional break-out or plugin boards for your motor control project?
For some applications it may be more cost effective to use an existing stepper motor controller or brushless ESC and purchase a custom made plugin board to deliver the features you require. This is generally the case where modifications are much more about physical user interfaces such as additional buttons, pots or displays and is often also true where additional communications types or similar are required. If you are anticipating relatively high volume (200+ a year) then it will probably be lower cost to get a custom made board. For anything below this, adding a plugin board could save you money.
Can I purchase the full intelluctual property of a custom stepper motor driver or brushless ESC?
The short answer is yes, however …
Yes, purchasing full intellectual property for a motor control design is an option but not one which is commonly pursued (or indeed encouraged).
The core business model through which we deliver value for money and attempt to spread technically advanced controllers at competitive prices is built on the accumulation of intellectual property and design knowledge then enabling us to deliver lower cost, customised motor control solutions. It is therefore clear that if we sold the design rights for every motor controller we had ever developed we would not be able to do this.
That said, we do understand that with certain projects, particularly those which are moving towards patents and copyright protection, that this is a key requirement. In cases such as this we will be happy to explore your requirements and advise. Sometimes this may include licensing, sometimes it can include a restricted intellectual property transfer agreement in which you purchase the design rights to the controller that you require with key documentation covering the limitations of this.
Formal legal agreements
Any Intellectual Property transfer will be subject to a formal intellectual property transfer agreement drawn up by our solicitors which will outline the exact terms of the agreement and which will be included as part of the overall quote.
Case by case basis
By definition, the requirements of each specific project are different and we therefore prefer to deal with IP ownership requests on a case by case basis.
To discuss this in detail we would suggest that you CONTACT US as this type of issue is best dealt with on a case by case basis.
You can also read more information about our bespoke motor controller design projects, or some case studies of motor control design work we have previously carried out.
How complex can the programming of the standard range of Zikodrive Stepper Motor Controllers or Brushless Motor Drivers be?
Hoe complex can the programming of the standard range of Zikodrive stepper controllers or brushless motor drivers be?
Why should I use a motor controller from Zikodrive?
One of the main advantages of using a Zikodrive motor controller is that our motor controllers are fully programmable. If you have need to control any of our standard range of controllers in real time then we have a range of potential options that can help with this. Alternatively, we can support you with custom firmware developed in house by our UK based tech team.
Quick set up of the basic parameters of your stepper motor controller or BLDC motor driver
At its most basic, we can set up a stepper motor controller with basic settings such as current and speed. This is particularly useful for those customers who require a motor driver that runs in a set speed range or who just need a motor driver which will accurately and repeatedly run at a set speed. Our aim here is to simplify things as much as possible for our customers by setting up the basic parameters on the stepper motor controller or brushless motor driver before you even use them.
Stepper motor drivers and brushless ESCS that make it simple and easy for you
The central aim of this type of programming is to deliver motor drivers which are set up and ready to go for the specific application that you need. Many of our customers have previously used stepper motor drivers or brushless ESCs where they have to try and manually set up specific speeds using either a pot or other mechanical methods (including breaking resistors off the PCB!) but with Zikodrive Motor Controllers we can preset exact parameters into your motor controller so that you can simply take it out the box and plug it in….
Once you have confirmed that you are happy with everything we will then assign a part number to enable you to re-order the exact pre-programmed controller that you need whenever you need it.
This is an option which has been taken by a larger number of UK, European and American companies who we now regularly supply with standardised Zikodrive hardware with bespoke firmware for their specific applications.
It is a proven path for getting customised motor controller performance at a stock controller price.
More complex programming of your stepper motor controller or BLDC motor driver …
As useful as the simple parameter setting programming can be in a range of applications it is just the tip of the iceberg of what can be achieved with Zikodrive Stepper Motor Controllers or Brushless ESCs.
For more technically advanced and demanding motor control applications we can set up motor controllers to run specific sequences. These sequences can then be triggered with a signal input or can be setup to be modified using external switches or pots. Always bear in mind that we can set up any motor controller to operate with a range of external user controlled inputs such as buttons, pots and more.
If you want to get a sense of the level of complexity that can be achieved then a good place to start is with the iD Stepper Motor Controller specifically developed for Boxer Pumps . This features a significant amount of complex programming in order to incorporate automatic pump calibration, dosing monitoring, a full user interface and second tier calibration interface and a whole host of other features.
Conclusion – Complete programming of stepper motor controllers and brushless motor drivers to meet your project’s needs
Just ask! If you have a specific requirement that you would prefer to be directly programmed into a controller rather than operated by UART or similar protocol then we are probably able to help. Products such as the ZD10 Stepper Motor Controller are designed to be customised and so we will need to work with you to develop your specific application.
How does closed loop control of brushless motors work, what brushless motor controllers do I need and what are the advantages?
How does closed loop control of brushless motors work, what brushless motor controllers do I need and what are the advantages?
What does closed loop brushless control involve?
Closed loop brushless control involves driving a motor but then monitoring the speed of the motor and using the monitored information to inform the behaviour of the driver. This then creates a closed loop in which the actual output of the motor is monitored and the controller drive adjusted according to the behaviour of the motor. This is particularly useful in applications in which there is a need to maintain an exact speed all the time or is also a useful method for monitoring for potential faults such as jams, stalls or where a sudden change in load could result in a potential undesired speed up.
There are (broadly speaking) two methods by which brushless motors can be operated in a closed loop.
The first is using a sensored brushless motor and using the onboard hall effect sensors to monitor the rotor speed and position. This can then be fed back into a brushless motor controller which can then process the information and change the way in which it drives the motor according to the core requirements of the application.
The second method involves using sensorless brushless motor controllers but then using the back electro-
Is one method better?
Broadly speaking, most engineers would argue that using hall effect sensors is ultimately the most accurate and therefore the best route to go down if you need a closed loop brushless system. This largely because the onboard sensors can tell you exactly where the rotor is and what speed it is doing and essentially do the job of an encoder but without the additional cost of buying an encoder.
That said, sensored motors and controllers do typically cost more money which can be a downside depending on other applications.
They also are ultimately less reliable than sensorless brushless motors because there are more things that can go wrong, typically the sensors. This is an especially important factor to consider in applications where there may be lots of dust or other issues which could interfere with the sensors.
If one of these sensors breaks then the controller will not be able to operate and this could lead to an expensive repair. To learn more about the differences between sensored and sensorless brushless motors and controllers and their applications click here.
Which brushless motor controller do I need for each method?
To use the sensors on a sensored brushless motor you will need to use a sensored brushless motor controller. A sensorless brushless motor controller will be able to drive a sensored brushless motor but not by using the sensors.
For a closed loop brushless system based on back-
This sensorless brushless motor controller will be able to drive either a sensored or a sensorless brushless motor controller in a closed loop system by using the back-
The type of brushless closed loop system we would recommend will ultimately depend on the nature of the project or application that you have. Both systems have pros and cons which are technical and financial and ultimately need to be considered in the context of your specific project.