Anyone use DC motors and need a cheap drive? (I did)

[Exuptoy]

Following my post a few months ago where my DC garage door motor drive failed, it has played up since the repair doing odd things like taking an age to start almost as if the start ramp had been put up to infinity thereby taking 2 or 3 mins before starting I decided to bite the bullet and buy a cheap Chinese drive from the bay of E.

It cost me less than £32 for the device which arrived from China in 20 days!! I ripped out the guts of my original drive and use the insulated posts from it just to allow a little airflow and keep it from the cold surrounding metalwork to ensure the condensation doesn't kill this one) and drilled a few new mounting holes and I now have a fully working 240v mains supplied 180v 4A DC drive which controls my 1/2 hp Baldor drive effortlessly.
I can now slow this down to a crawl of give it full beans which I couldn't do with my old drive as the speed control was toast and only gave me max speed.

It's smaller than the previous guts with no chunky transformers or anything. Terminals from left to right are power switch (x2), potentiometer (x2??) A+/A-, F+/F-, Mains (x2).

Hope this is of use to someone.

http://www.ebay.co.uk/itm/112174804318?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

[Windy Miller]

Can the output voltage be fixed at any point? I have a 130v DC motor that I'd like to try out...

 

[ukracer]

Can the output voltage be fixed at any point? I have a 130v DC motor that I'd like to try out...

And me....lol

 

[Exuptoy]

DC is 0-220V so it should work with any DC motor in that range. The pot will give speed control but can be left in any position too.

 

[ukracer]

DC is 0-220V so it should work with any DC motor in that range. The pot will give speed control but can be left in any position too.

Just got to work out how to limit it to 130 max etc then

 

[Pete.]

Just got to work out how to limit it to 130 max etc then

Make the pot part of a voltage-splitter circuit. Easy peasy.

 

[ukracer]

Make the pot part of a voltage-splitter circuit. Easy peasy.

lol might be for you...I am getting rather old now. lol

 

[Windy Miller]

Make the pot part of a voltage-splitter circuit. Easy peasy.

Yeah right. Easy peasy! I'll be calling on you about that Pete!

 

[Exuptoy]

Here you go, some light reading.

http://electronics.stackexchange.com/questions/24031/potentiometer-to-change-voltage

 

[Pete.]

A pot IS a voltage splitter/voltage divider. Anyway let's say you have a controller that takes a 0-10v signal and puts out 0-180v. You have a motor that needs pegging to 130v so here's what I would do (I'm sure there's a more elegant way with voltage regulators and zener diodes or whatever but I struggle with electronics myself):

I'd get 2 pots, say 5kohm each, Put one across +10v and ground and put the other across the output of the first pot and ground, the output of the second pot is the signal voltage for the motor speed controller. Turn the second pot all the way to zero ohms then use the first pot to set the max speed/voltage you require (like 130v). Now the second pot can only let the motor go from zero to 130V.

 

[Exuptoy]

But surely the pot fitted to this controller limits the armature output to whatever speed you set the pot to so just set it at zero then wind it up until the output is at 130v. The only problem then is there is nothing to limit it to 130v max as you could wind it up by mistake.

 

[Pete.]

Exactly, but then again how much harm would it do? The worst could happen is you cook the windings.

Adding the second pot allows you to set a top limit. I have a similar thing controlling the field voltage on my lathe's DC motor except it sets both a top limit and a lower limit of 45v

 

[gaz1]

ohh this threads just come in handy thanks for posting it as ive got loads of motors to play with that will just suit this application

 

[Seadog]

Use preset pots.

 

[Kram]

If you want to protect from condensation you can get the pcb out and a coat of clear acrylic spray

 

[MBB]

I bought one of these works good. £16

https://www.ebay.co.uk/itm/AC-220V-...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649