How to rectify ac to run a dc motor?

The figures seem to be right. The mean voltage of a rectified sine wave is Vrms*0.9.
The volts, amps, power are consistent.

I cannot help with the smoke.

 

Can you post the make and model of the motor or where it came from?

 

Greetings, I have small passing familiarity with DC motors and have never seen such strange specs...
130VDC (not 13VDC huh, hmm)

If you have DC power supply to vary the volts and current to your perm.mag motor, slowly increase current

Else you can try to use big power resistors/rheostats to estimate the motor's resistance through its stall current (i.e- increase rheostat's resistance untill current level can't turn motor).

Sorry, I have no real world experience to offer you.

 

If he has a DC power supply he could just steadily increase voltage and check RPM to see if there's a misprint. Most likely, the smoke is the oil burning off though. A brushed DC motor shouldn't be wet with oil anywhere near the brushes. My suggestion would be to degrease the motor insides and dry it well, then try it again.

 

You need to determine the type of motor, If it is a permanent magnet motor then there will be some external magnetic field and there will probably be some 'cogging' where the motor goes round in slight jerks when turned by hand.
If it is a shunt motor, there will be a field winding which must be energised before the brushes have power.
It is not likely to be a series wound motor since it is DC.

Since you have taken it apart, check where the wires go to with a meter. Two could go to the brushes and one to the field, the other end of the field may go to a brush.

In any further test, put a bulb in series to limit the current, you could also try it at a lower voltage. My battery charger gets abused for such jobs.

 

That looks as if not too much damage has been done.
Measure the voltage on the spare wire relative to each of the input wires. Is it connected to the body?

A common light dimmer is not just a rheostat, it is a phase controlled triac. It may work but may give complications.

Use a filament bulb to limit the current. Start with a low wattage and work up. See if the bulb lights brightly before the motor starts to turn. You may need a slow start circuit.

 

Hi
That'd be a case of "suck and see". (BTW a light dimmer is not a rheostat although a rheostat can be used to dim lights). You sound pretty cautious, so I'd say go ahead. However there's a chance the inductance of the motor could upset the "triac phasing" in the light dimmer, so if things seem to be going out of control another approach will be needed.

(I see that Duke has recommended similary. Use his idea about the (tungsten filament) light bulb, they're great at saving electrical parts under test!

 

what voltage is the light bulb rated for please? and what voltage was being supplied to the circuit?

this smoke does not sound good. Is it really acrid, richly nasty chemical type smoke?

 

and this your circuit? (see attachment)

 

What are the bits attached to the brushes? Normaly they slide in a metal sleeve and have a spring at the back to keep them at the right pressure against the armature.

It looks like a permanent magnet motor with red and black for inputs as you have used. Does the green wire go to the case?

Edit. If you put a bulb across the motor, this may provide a load sufficiently resistive to make the dimmer behave.

 

This is very unusual. It's still smoking after you degreased it and tried again? Could it be a bad rectifier? The motor runs fine on the battery but not so much on rectified DC. Out of curiosity, if I had the motor, I'd probably spin it at the rated RPM and see what voltage it generated. If that checks out it would seem to me that you definitely have an issue with the rectifier. Either damage or improper connections somewhere.

 

Are you sure that the Motor is 130v?