Dryer motor

Alright folks, after my last posting of the washing machine motor failed to prove helpful, ( because of my lack of understanding, not the help offered, that was excellent ) I decided to scrap that idea and start anew, this time with a dryer motor. I have a motor here now that like before I simply want to be able to start and stop at will. This time around I have the original wiring diagram too! So, my question is how do I wire the thing, simply with an on/off switch? No variable speeds, no reverse directions, just on/off. Oh, and Id like it run on 110v as well.

Picture of Dryer motor
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lukeyj155 years ago
I have a centrifugally switched 240v dryer motor. I have two wires coming from the wall. And three wires coming out of the motor. There is also the centrifugal switch attached to the motor. To get the motor to work at all, I connect either the red or yellow wires coming out of the motor to the hot wire from the wall, and the blue wire attached to the neutral. If I turn the motor on at this point, it will buzz/hum loudly at me without actually turning. After giving it a small spin in either direction, it will spin up and run normally. I was thinking that the unused yellow or red wire probably had a similar voltage to the wall on it due to the design of the motor. (the unused wire would act as a generator.) I successfully managed to run some lights by connecting them between the neutral and the unused wire. But if I left them connected and started up the motor it would spin up without my assistance. So by connecting the light (150w halogen (convenient test as it's not concerned about low voltages) to the normally closed side of the switch, it will act as a load and spin up the motor until the centrifugal switch cuts in and turns off the light. So the light will come on for about 1 second and cut out.
tauhid7 years ago
Suppose I can't see the original colours of the three wires come out of the burnt dryer motor just say brown (Brn, black (Blk), and blue (Blu) and the specs of the capacitor; I found used motor with wires in different  colours from the "original" say white (Wht), green (Grn), red (Red).  If the resistances between Wht and Grn  57 Ohms, Wht-Red   24 Ohms, Red-Grn 80 Ohms (all are approximates; with simple AVO-meter), what is the right size of the capacitor? Which wires for the capacitor ?    Which wires are to electric line? I used to wire as told by the scrap motor supplier, which sometime ended in only few days of the motor services.
Yeasayer8 years ago
This will get you going if I haven't missed something. There are wires coming out of the motor connection box that are used to shut down when different drying times are selected on the timer, they can be cut from branched connectors in the box. make sure the other branch connects to the motor winding with good electrical contact. PURPLE, BLUE, RED, (RED & BLACK) Can be removed. Don't cut Capacitor Wires WHITE & RED. Would like to know if this helped.
is this box below the motor automatic start switch ? if its just a contactor than what switches it (disconnects the capacitor) after few seconds ? can the capacitor be left connected all the time ? (in all appliances i know (240 V 1 ph) it is)
The Capacitor disconnects by way of an electrical switch inside the motor housing, it is operated by spinning weights on the armature. I did not show this in my reply because this should be a built in already connected. pin #2 supplies the power to the internal switch as well as the run winding coils, the Said switch powers the starting winding through the Capacitor.
is that contactor (under the motor in the drawing) actually built into the motor ? why are it and the motor drawn separately in the scheme then ?
Yes it is. This is electrical Drawing, There seems to be Taboo on showing any mechanical parts , The switch is a mechanical device and only the contacts are noted. another pic. for you.
that makes it clear thanks :) but i still dont get it completely there should be more wires coming from the motor ? (extra 2 for the switch). they should go then between the motor and the box but they are missing in the drawing in the photo above. the drawing also makes clear to me that the switch is not just there in series with the start coil inside and are those motors really different from the 240 V motors i know ? if yes then why ? th motors i know dont have any switch like that. i opened few motors up to 1 ph 200 W and one 1 ph 1500 W. in all the wires are hard wired to the coils. the rotor is not connected to anything - no brushes etc. there is nothing that can act as or control a switch other stuff that shows that the capacitor is connected all the time - if you disconnect the capacitor when its running it stops and goes zzzzz. you can change the direction in some motors if you move the capacitor to the other coil. that would be impossible with switched motors cause it would switch off the now main coil when it reaches high enough speed
The motors you have looked at are named capacitor run split phase, they function the same as the centrifugal switch split phase but the motor winding
is modified to accommodate a full time phase shift.
Here is a link that has some good information on electric motors.
that link explained all. thanks !
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