Dc motor - SCR - BR help.

[Terry Halstead]

Hi guys, I'm in the making of a 2x72 belt grinder. Using a dc treadmill motor. I have bought a speed controller from eBay and a bridge rectifier. I need help in wiring it all up.

Specs
15 amp 600volt 4 pin single phase bridge rectifier

Ac 220v 50hz/60hz 400w single phase speed controller output DC 0-220v

1.5 hp 750w dc 220-240v 5A treadmill motor

 

[Terry Halstead]

Hi guys, I'm in the making of a 2x72 belt grinder. Using a dc treadmill motor. I have bought a speed controller from eBay and a bridge rectifier. I need help in wiring it all up.

Specs
15 amp 600volt 4 pin single phase bridge rectifier

Ac 220v 50hz/60hz 400w single phase speed controller output DC 0-220v

1.5 hp 750w dc 220-240v 5A treadmill motor

 

[kellys_eye]

Do you have the full spec of (or a link to) the speed controller?

It would appear that all you need do is connect the mains supply input and the motor to the output. The bridge rectifier is not required.

 

[Terry Halstead]

Do you have the full spec of (or a link to) the speed controller?

It would appear that all you need do is connect the mains supply input and the motor to the output. The bridge rectifier is not required.

Thanks for fast response. Link is http://www.ebay.co.uk/itm/AC-220V-4...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2648

 

[kellys_eye]

Well it's a 400W speed controller and you're connecting it to a 750W motor...... although it may get the motor spinning, as soon as you load the motor (press on the sand belt) the current consumption may exceed the capacity of the speed controller and, at best, blow the fuse. At worst, blow the controller up.

Your principle is sound but either get the correct rated motor or the correct rated speed controller.

 

[Terry Halstead]

Thanks. I have also ordered this for the same reason you said. I saw a guy on youtube using and recommending this one with the BR and similar DC motor.Would that be the best way to do this then? http://www.ebay.co.uk/itm/AC-220V-1...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

 

[kellys_eye]

No. That device is a controller for AC motors, not DC. The motor is wired in series with the AC mains supply and controller. Fitting a bridge rectifier (to convert it to DC) won't work (properly) as the AC waveform is necessary for the speed controlling circuit to work.

 

[Terry Halstead]

OK thanks so I wired it up and it's all working. But like you said on high power and under load it will trip out. So I need one for 750w. Any recommendations on one? Much appreciated buddy thanks for your help.

 

[Minder]

You Can use a Triac controller with a DC motor, just place the bridge after the Triac and and wire the motor 'inside' the bridge.
The Chinese often use 'SCR' instead of 'Triac'.
Generally they are used for Universal motors.
It gives you a similar control to the KB DC SCR bridge motor controllers which are a bit more sophisticated but more $$'s
M.