How to build a controller for 90 VDC motor ?

[Maferic]

Does anybody can help me to design a controler for 90 VDC motor ?
I have an idea using AVR microcontroller operating in PWM mode and connect it to H- Bridge to drive the motor. Is it correct ? But after googling I can not find the H-Bridge that can be operated until 90 VDC, mostly just only 55 VDC operation. Or maybe does anybody have more better idea for the controller ? Thanks for your help.

 

[Ubergeek63]

so you ripped a motor out of an old treadmill... do you want it to go both ways? generally the only difference is the power parts as long as the level shifters can take 300V or more.

 

[stevez]

I have two Baldor 90 vdc motors, 1/2 hp down in my workshop with speed controllers. I rather doubt there is much control but there is a zero to 100% adjustable range. I've not examined the circuit but the controller, as I understand it is very basic and low in cost. I don't think the controller uses odd parts but rather more likely that the parts are quite common, at least to the manufacturer of the speed control.

 

[Maferic]

My application is a customized application for 100 VDC power source and also need a small board size because of space limitation. Because of that I must design by myself for the controller to suit its needs.

 

[Reloadron]

I was working quite a bit with Bodine fractional HP motors both Brush Type and Brushless PM type (I don't know what you have). I generally just use Bodine or Dayton controllers. If you look down this page you will see some open chassis (just board assembly) DC motor controllers. These are for PM type motors (2 wires). The same sort of controllers can be had for Brush Type motors using 4 wires (fixed field).

Unless you are fixed on PWM these controllers work fine and have lasted forever.

Ron

 

[Ubergeek63]

My application is a customized application for 100 VDC power source and also need a small board size because of space limitation. Because of that I must design by myself for the controller to suit its needs.

again: details please.

you do not mention the power levels you are looking at, what sort of speed feedback you have, or if you need it to be reversible... oh and station keeping is another whole bucket of worms. In short, you have not supplied the info needed to even begin.

do you need 1 amp or 100? do you need speed accuracy? do you need control at 1%? I have designed all of that but you do not say anything but 90V and and small size... at 1/2HP unidirectional it is doable, but not at 1HP+ or bidirectional. of course your idea of small might not be the same as mine.

EXACTLY what motor do you have? EXACTLY what do you expect it to do? EXACTLY how much space do you have? .... you get the picture.

 

[Hero999]

The simplest way of controlling the is to use a transformer, a bridge rectifier and a lamp dimmer circuit.

You haven't filled your location in.

If your mains voltage is 110V, you might be able to get away with omitting the transformer and powering from a bridge rectifier connected directly to the mains.

If your mains voltage is 230V then you'll need a transformer to reduce it to a lower voltage so you can power your motor.

This is not the best method of controlling the speed, it's single direction only (unless you have a DPDT switch after the rectifier) and the torque characteristics aren't as good as powering it from DC and using PWM.

 

[Maferic]

The voltage is 220 VAC.
Ok thanks for all your help

 

[Hero999]

Then you just need a 90V transformer, a bridge rectifier and a lamp dimmer.

My local supplier sells transformers with twin 45V secondaries which can be connected in series to make 90V.
**broken link removed**

Connect the bridge rectifier to the transformer's secondary and the motor to the DC side of the rectifier Do not use a filter capacitor, other than a tiny RF supression capacitor (<1µF). Connect the lamp dimmer in series with the transformer. Make sure the lamp dimmer is compatabile with transformers (i.e. is suitable for low voltage halogen lighting) and has a high enough power rating.

I'll post a schematic, if you're not sure.

 

[Ubergeek63]

Then you just need a 90V transformer, a bridge rectifier and a lamp dimmer.

My local supplier sells transformers with twin 45V secondaries which can be connected in series to make 90V.
**broken link removed**

Connect the bridge rectifier to the transformer's secondary and the motor to the DC side of the rectifier Do not use a filter capacitor, other than a tiny RF supression capacitor (<1µF). Connect the lamp dimmer in series with the transformer. Make sure the lamp dimmer is compatabile with transformers (i.e. is suitable for low voltage halogen lighting) and has a high enough power rating.

I'll post a schematic, if you're not sure.

well that will work if you like hearing double line frequency grinding away at your bearings...

 

[Hero999]

Have you actually done it before?

If you did, you'll find that it's no worse than a universal motor which is used in many household appliances from a food mixer to a vacuum cleaner.