PDA

View Full Version : Motor wiring question



jd4020d
01-11-2005, 10:06 AM
I have an E12 motor I would like to use to power a 2 stage snowblower, my question is what to do with the 4 wire plug -- which I read was for the armeture and the 2 wire pluge which I read was for a safety switch?

Any information would be greatly appretiated.

Thanks,

Todd

Markus
01-11-2005, 09:24 PM
Two of the wires go directly to the battery (to power
the motor field), the other two can either just be left
unconnected or can be used in in series with a big
contactor. The contactor would be used to turn on the
motor and the internal overload switch could cut power
to the armature if needed.

To find out which two are for the field just measure
between two adjoining posts. The ones of the safety
switch will have virtually no resistance. The field will
have a couple ohms resistance (I think 11 Ohm)

Hope this helps

Markus

jd4020d
01-12-2005, 12:18 PM
Thanks Markus, that gives me a place to start. Since I am still kind of new to this, I most likely will have more questions as I go.

Todd

Walt Konstanty
01-14-2005, 12:06 PM
Make sure it is power and thermoswitch.....it may be field power and armature power - reversing the polarity on the field makes the motor run the other way (field leads are smaller with higher resistance). A thermoswitch is either NO or NC. For a normal drive motor (like E-15/E-20) the field is reversed by that little finger relay. Armature (high) power stays same from big contactor.

If thermo switch, do not hook them to a contactor as the thermo switch cannot take full amps and is not meant to. It's actually connected in series with the power to the contactor that turns the drive motor on....that is low power. You could connect a lightbulb to the thermo switch but need to determine if it is NO or NC.....pick a bulb voltage which matches the motor voltage - 36V, or use an LED and resistor.

Don't blow it up....motors are hard to find !

..Walt

Markus
01-14-2005, 08:26 PM
>Make sure it is power and thermoswitch.....it may be field power and armature >power -

No it may not. The armature is never on the small connector (the current that needs to flow through the armature would melt the small connector away) The armature is always connected with large posts. The field in turn only draws about 4 Amps (I think the field resistance is 11 or 16 Ohms).

you can take a look at http://markus.lorch.net/et/drive-motor-test/05060005.JPG, which shows an E20 drive motor. On the left side the field connections are hooked up to a 6V batt and on the right side the armature is hooked up to another 6V batt.


> reversing the polarity on the field makes the motor run the other way (field leads are smaller with higher resistance).

correct

>A thermoswitch is either NO or NC.

the one we have here is NC (normally closed)

>For a normal drive motor (like E-15/E-20) the field is reversed by that little >finger relay.

I think this is not correct for the E20, here actually the armature is switched (why I don't know) - this is being done with 4 large, interlocked contactors forming an H bridge

>If thermo switch, do not hook them to a contactor as the thermo
> switch cannot take full amps and is not meant to. It's actually connected in
> series with the power to the contactor that turns the drive motor on....that is >low power.

Thats exactly what I intended when I said in series with a contactor ... I meant in series with a contactor coil ... to if the termo switch opens the contactor will drop out and cut current to the armature.

Markus
01-14-2005, 08:31 PM
On another note: I was surprised to hear that the E12 also has a temperature switch. I thought that was only on the E15 and E20 motors.

Dennyjoe
02-10-2005, 11:11 PM
The original snow blower that was on my E8 had a 3 wire connector on it. I converted that selonoid switching contraption that came on it into a SCR controlled device.

After much thought as to what was going on there, I determined that the reason there were three wires was that when the blower shuts off that the motor has a contactor that shorts across the motor (after power is removed), to dynamically brake that huge motor on the blower.

I used commutating scr's to simulate those mechanical #&*((%))$@ contactors.
As you can probably tell, I don't like mechanical thing that break. and rust and freeze-up. Especially when you got a couple of feet of snow!!!