Archive through February 27, 2007

 

Technobots FAQ » Motor Speed Controllers & General Electrical » Speed Controllers » Can you recommend a speed controller? » Archive through February 27, 2007 « Previous Next »

 

Author Message
mike baker (Mike)
Member
Username: Mike

Post Number: 1
Registered: 9-2006
Posted on Thursday, September 14, 2006 - 5:49 pm:    Edit Post    Move Post (Moderator/Admin Only)

im building an electric car to race i have an 24volt 240 watt 2000rpm fracmo motor it has 4 wheels and carries a person what speed controller would you suggest no reverse is needed
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 266
Registered: 10-2004
Posted on Sunday, September 17, 2006 - 8:10 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hello Mike,

Just to confirm our telephone conversation, the ideal speed controller for this application is the 4QD uni 4, 24V as you do not require reverse and you need a throttle type pot input. It is also quite possible that you will not need a heatsink for continuous operation but I would recommend the optional base plate and box for robustness.

Regards

Paul
nathan
Unregistered guest
Posted on Wednesday, December 13, 2006 - 2:55 am:    Edit Post    Move Post (Moderator/Admin Only)

hi, i would like to know which battery and speed controler are best to go together for 2x 12v moters.
i tried reading through the info with batteries and speed controllers and i cant understand it.
as a beginner i dont want to waste money by blowing up my first speed controller.

thanks nathan
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 355
Registered: 10-2004
Posted on Wednesday, December 13, 2006 - 6:36 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hello Nathan,

We will try and help but you need to give us more to work with. Do take a look at our forum especially in the Can you recommend a speed controller section? The first thing to sort out is the power rating of the motors and how long do you want the batteries to last. We supply motors from just a few watts to a thousand watts so the speed controller has to be matched to the motors.

So, please give us as much info as possible and we will do our best to recommend the right products.
alfredomontenegri
Unregistered guest
Posted on Sunday, February 11, 2007 - 1:32 am:    Edit Post    Move Post (Moderator/Admin Only)

Hi,
I am looking for a 12-24v motor controller that can receive serial string commands and positional feedback from a potentiometer effectively creating a 'giant' servo - control commands would be from a pc serial port
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 396
Registered: 10-2004
Posted on Monday, February 12, 2007 - 12:37 pm:    Edit Post    Move Post (Moderator/Admin Only)

Alfred,

We have two models from Pololu that may well suit your application. One rated at 3A (1503-004) and the other at 30A (1503-006). Both will take a serial input string but you will need to use an voltage level converter interface between the PC and the controller (our part no. 3810-002 for example).
alfredomontenegri
Unregistered guest
Posted on Monday, February 12, 2007 - 10:53 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi Paul,

Thanks for this. I am using the scott edwards SSC servo controller board which is controlling normal sized 'hobby' servos. Can this be directly connected to one of the motor drivers(with motors connected) you mentioned creating a 'giant' servo?

Many Thanks

Alfredo.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 397
Registered: 10-2004
Posted on Tuesday, February 13, 2007 - 12:33 pm:    Edit Post    Move Post (Moderator/Admin Only)

Alfredo,

This is also possible with the same two Pololu controllers referred to previously. The controllers can take a serial data stream from a microcontroller or via an interface from a PC. Also from an analogue signal (varying voltage). Or from a standard 1-2mS pulse signal from a RC radio receiver, servo controller or in fact any device that emulates the 1-2mS signal.

To use it as a giant servo controller, use a position pot to feed back a voltage thus putting the controller into closed loop control. It is possible to alter the PID control loop terms via the serial data connection. If you are not familiar with PID control loops, there is some help in the respective data sheets which can be found on our website or search the internet. Do not get bogged down by the maths. Having spent many years in the process control world, tuning a PID loop can be relatively straightforward for simple closed loops. When you come to tuning the loop and find you are having difficulties, let us know and we will assist.

Regards

Paul
Jeff Green
Unregistered guest
Posted on Monday, February 12, 2007 - 6:27 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi,
I am looking for a speed controller for a 12volt motor from a Vauxhall Nova power steering. It is made by NSK(13 136 674) runs at 1800rpm and 5.5Nm torque has been mentioned. Can you help?
Regards Jeff
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 398
Registered: 10-2004
Posted on Tuesday, February 13, 2007 - 12:40 pm:    Edit Post    Move Post (Moderator/Admin Only)

Jeff,

The part number does not mean anything to us, what we really need is the current consumption or power rating. This must be a reasonably sized motor, maybe as large as 1HP to produce that torque at that speed. Don't hold us to it but you could be looking at 60A running current. I assume you do not need it reversing if it's for a power steering pump unless you are going to use it for a different application.

Best guess with the info supplied, a VTX 75 if reversing or a Uni series 8 if non-reversing. If you can confirm the current or power, we can confirm our best guess.
alfredomontenegri
Unregistered guest
Posted on Tuesday, February 13, 2007 - 9:04 pm:    Edit Post    Move Post (Moderator/Admin Only)

many thanks for your quick response and help.

Alfredo Montenegri
Simon Theaker
Unregistered guest
Posted on Sunday, February 18, 2007 - 5:13 pm:    Edit Post    Move Post (Moderator/Admin Only)

I intend to build a crude CAD/CAM demonstration "robot" as part of a college project. I was thinking of using three of your 24V 200W Geared 9.778:1 MY1016Z2 motors to achieve full three axis movement. When I say crude, no feedback required, and only single motor direction so no large reversing current generated (yes, very simple I know..)
Due to requirements of the product and that it will be statically installed, I would prefer to use mains supply to power the motors.
Can you advise me as how to use 230v 50Hz supply in powering this type of motor & what type of controllers/power conditionong/voltage transformation will be required.
I am afraid that my electrical engineering knowledge is limited so any advise would help enormously.
Many Thanks.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 400
Registered: 10-2004
Posted on Sunday, February 18, 2007 - 8:22 pm:    Edit Post    Move Post (Moderator/Admin Only)

Simon,

Firstly, this particular motor has just been discovered as being 250W not 200W. However, same size, same price etc.

Do you require speed control or on/off control. As the motors require 24Vdc to achieve full output power although reduced power output from a lower voltage may be suitable for your application. Three motors at full power could be drawing 45A, how long and how frequently do you require the robot to run for?
Simon Theaker
Unregistered guest
Posted on Monday, February 19, 2007 - 1:23 pm:    Edit Post    Move Post (Moderator/Admin Only)

250watt/motor is even better, thanks..
To answer your questions.. The three motors will experience different load duties. 2 at 25% load duty and the other upward of 100% for extended periods (10-15 mins).
Yes, I would like to control motor speed and power on/off.
Lastly, I already have ideas for uses for the motors beyond the project in which they will initially be used, therefore I would prefer individual 240v power supply and controller for each motor.
Many Thanks
Simon
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 401
Registered: 10-2004
Posted on Tuesday, February 20, 2007 - 7:34 pm:    Edit Post    Move Post (Moderator/Admin Only)

Simon,

You could still see a load of 20 to 25A. You did not say the frequency which could influence the answer we give. Motor speed controllers are not keen on being run from switch mode power supplies which are the most efficient type with these higher currents. If the frequency was only once per day, I would recommend a pair of batteries with a charger. For a power supply, I would suggest a linear power supply of at least 25A @ 24Vdc.

How do you wish to alter the motor speed? Is it a potentiometer, radio control, computer?
Simon Theaker
Unregistered guest
Posted on Wednesday, February 21, 2007 - 1:31 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi,
I would anticipate maximum frequency of use (when in use) at:
ten sessions of 15 min use at typical 40-80% motor speed within each working session (i.e. working day - 8 hours).
(1-2 working sessions/week)
The possibility of batteries failing part way through session makes their use non-preffered.
Method of motor speed control - simple potentiomoter (later possible positional feedback control - but much later... if at all)
Linear PSU, fine as i'm not too interested in overall system efficiency, and very interested in keeping costs to minimum.
Can you recommend lin-PSU model / manufacturer?
& speed controller?
Again, many thanks for your help.

Simon.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 404
Registered: 10-2004
Posted on Thursday, February 22, 2007 - 9:55 pm:    Edit Post    Move Post (Moderator/Admin Only)

Simon,

That use would mean a relatively large battery. We stock power supplies up to 40A which whilst large enough are switch mode. They may well work but would be better with some additional capacitance on the output. Ebay frequently has linear power supplies so you could check that out.

For the speed controllers, I would suggest our Uni series 4 24Vdc.

Hope that helps.
Jeff Green
Unregistered guest
Posted on Monday, February 26, 2007 - 3:14 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi,
Further to your reply (post No. 398) I have just purchased a DC ammeter and can confirm the following:
No load 4amp; Heavy load 50amp; Stall 120amp. In it’s application it is very unlikely to stall, so I assume your best guess of a VTX 75 would be sufficient, does it have overload cut-out? I shall need two speed controllers. We have a couple of 2 channel TX / RX from old remote car sets, would the output from the car RX (without the servos) be any good for your speed controllers? I’ve got to keep costs down this is a charity project. Regards, Jeff Green
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 410
Registered: 10-2004
Posted on Tuesday, February 27, 2007 - 12:58 pm:    Edit Post    Move Post (Moderator/Admin Only)

Jeff,

Good information there. Yes still happy to recommend the VTX 75 on the basis that you would not normally run above "heavy load". The VTX has a current limit and I would also suggest a line fuse of 60 to 70A in the power supply lead to each controller (see our electrical section).

For a RC input, you need to make sure that the Rx follows the industry standard 1-2mS pulse output. If you can plug in a Futaba servo for example and it travels approx 120 degrees of rotation, then it should be fine. These speed controllers look for a voltage input so you need an interface. If you are looking to control each speed controller independantly from each Rx/Tx then two off our 3401-003 will work fine.

If you need any further assistance, we will do our best to help.
Jeff Green
Unregistered guest
Posted on Tuesday, February 27, 2007 - 11:10 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi Paul, re-your reply (post410) could I use 1 of your 3401-004 interfaces with a 2 channel TX to control the 2 motor speed controllers fwd/rev?
This is for tank type steering on a 4WD robot. I've read on this site about splat problems with cheap TX kit, could this be unsafe with a heavy robot?