Help w/ Single Phase AC Motor wiring? (not HW)

Click For Summary
SUMMARY

The discussion focuses on wiring a 1/3 HP, 1000 RPM, 115-volt single-phase AC motor from a garage door opener to a three-pronged 120V plug for use in a grain mill. The motor has four wires (White, Green, Red, Brown) and a dual capacitor with specific wiring requirements. Participants emphasize the importance of measuring ohm readings between the motor wires and the frame to identify the correct wiring configuration, and they suggest verifying the ground wire and checking for any internal switches that may affect operation.

PREREQUISITES
  • Understanding of single-phase AC motor wiring
  • Familiarity with multimeter usage for measuring ohms
  • Knowledge of capacitor functions in motor applications
  • Basic electrical safety practices when working with AC circuits
NEXT STEPS
  • Research how to measure ohm readings accurately with a multimeter
  • Learn about the role of start and run capacitors in AC motors
  • Investigate wiring diagrams for similar AC motor applications
  • Explore troubleshooting techniques for single-phase motors
USEFUL FOR

This discussion is beneficial for DIY enthusiasts, electrical engineers, and hobbyists looking to repurpose AC motors for home projects, particularly those interested in motorized grain milling.

MotorNewb
Messages
2
Reaction score
0
Hey all. I have an old garage door opener motor. Its a 1/3 HP, 1000 RPM, 115 volt, 3.6 amp, AC Motor (Am I correct in thinking its single phase?). I'm attempting to motorize a grain mill that I have in the kitchen. (the faster I can grind the wheat the faster my wife can make homemade bread right? ;)

I am following a similar design as this guy:
http://sdcollins.home.mindspring.com/GrainMill.html

The Motor is a bit older and the wires had a good layer of dirt over them when I pulled it out of the garage door opener frame. However with some cleaning up I've exposed 4 wires:

White, Green, Red, Brown (They are unmarked other then color and enter the motor casing by the same hole)(See attached diagram)

I also have salvaged the dual capacitor which has a yellow wire(attaching the two together), a blue wire attached to one, and a red wire attached to the other. (See attached diagram) Also, the capacitors are encased in plastic, not metal, and therefore do not need to be grounded?

GOAL: Correctly wire the motor and the capacitors to a normal three pronged 120v plug, with a simple switch installed. I'd also prefer the motor to spin clockwise.

I've searched the internet and spoken with friends but haven't been able to figure it out.
Any pointers would be appreciated!

Thanks!
 

Attachments

Last edited by a moderator:
Engineering news on Phys.org
Do the capacitors have a value marked on them that you can see?
 
Yes,

GENERAL ELECTRIC
35F1150BA8
80-96 MFD
220 VAC 60 CPS
 
I will assume that the green wire coming from your motor is a ground wire. You should verify it by using a continuity meter and checking to see if it is connected to the chassis of the motor. Most garage door opener motors are not meant to be run for long periods of time. They will overheat. So this could likely be pointless.
 
The guys here can figure this out but they need some more information...
and it's a little hard to ask the questions succinctly.

so here goes -

do you have a multimeter that can read ohms? You can get one for $9.95 at Walmart.

could you make a matrix with all these ohm measurements in it?
the ohm readings should be one of three: zero, or infinite or just a few ohms- less than ten.

Difference between start and run winding ohms will be not very much. so be meticulous and use lowest ohm scale.
Before starting, check that meter reads zero with leads shorted together.


...Ohm Readings:.....
green to motor frame __ohms (hopefully zero)
red to motor frame (hopefully infinite)
brown to motor frame "
white to motor frame
"
red to brown
red to white
brown to white

red to green
white to green
brown to green

..end readings .......

lastly is there a switch on the motor that's actuated when the shaft gets to speed? Often this is internal to motor, look carefully.
A plastic capacitor is usually only for starting so there should be a switch, unless those caps are labelled "Motor Run". I have been unable to find that GE part number perhaps it's a special for the garage door company.

If you find the switch and can actuate it with a small dowel or something, see which of above ohm readings it changes. Repeat them all and add a second set of readings "with switch manually acuated"

another hint - when your ohm-meter is reading between two wires, twirl the motor shaft a little with your fingers.
If the two wires have a winding between them the ohmeter will deflect momentarily as you start to spin the shaft.
If the two wires just go into motor and are connected to same point, that is there's no winding between them, you won't see that brief meter deflection.

here's a link with a guess by a motor guy - see 'e bodine' and be aware he was guessing.
http://www.instructables.com/answers/Can-a-garage-door-motor-be-connected-directly-to-A/


Your ohm readings will be a big help.
 

Similar threads

  • · Replies 12 ·
Replies
12
Views
6K
Replies
0
Views
2K
  • · Replies 19 ·
Replies
19
Views
4K
  • · Replies 6 ·
Replies
6
Views
7K
  • · Replies 1 ·
Replies
1
Views
9K
  • · Replies 26 ·
Replies
26
Views
3K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 7 ·
Replies
7
Views
3K