AboutCharles C. Jones Expertise Let Me help you with your problems with single phase and three phase electric motors. I can tell you how to troubleshoot your motor problems. From simple testing of capacitors, how to test your windings, replacing bearings, and general maintance. Before we go any further, remember these words of advice: Disconnect the power before you do anything! Please limit your questions to electric motors and there immediate components. I review each question, and if I can answer or help, then I will. If you receive a rejection, it means it is out of my expertise, and just do not have the answer. I'll be waiting for your question, and see if I can help you. Thanks for using AllExperts!
Experience I have 30 years experience in the repair of electric motors and related equipment. I am a master machinist in the field of motor repair. I have been employed with my company for 27 years. When you ask your question, give me all the information you can about your problem. I have a lots more to add, but for the everyday do-it yourself kinda person, it might get to technical. So ask away, if I can't give you a good answer, I'll find someone who can
Expert: Charles C. Jones Date: 6/10/2008 Subject: 3/4 HP 110/220VAC Cap Start Doerr Motor
Question Motor appears to be wired permanently for 110VAC; Run windings are joined internally {with T1 to T3 and T2 to T4}
Motor has a three-wire "stationary" switch controlled by the centrifugal/mechanical switch. One internal wire [marked "J something"] goes to one terminal of Cap; the other two wires [J10 & J11] go to external wires [a Red and a White/Black, respectively].
The "Other" Cap wire [internally marked T8] goes to Start winding. The Start winding then goes externally to T5, a White wire.
This trolley motor direction was constantly reversed.
Questions:
How does this stationary switch work? How is it hooked up externally to provide for CW/CCW rotation?
If say, the T5 wire was wired HOT/L1, what did they do with J10 & J11? I am assuming this scheme is for CW/CCW control....???
The external Blue & Orange wires go to an internal "Thermostat" buried within the stator...are these the typical P1 & P2? If so, is the thermostat wired externally to some over-temp alarm, or is it wired in series with the Run windings? Thank you, Charles
Answer The stationary switch you are referring to I believe is a instant reverse switch. It is made so that one set of contacts are always closed. This keeps the motor from having to coast down, and let the centrifugal switch come to rest. Other than making connection for the start winding, it has no part in the actual reversing of rotation. This must still be done with a contactor or drum switch, by reversing T5 and T8.
As for the J numbered wires, these are not normal numbers in the wiring schematics that I have. At the moment, I just can't get a mental picture of how this is connected. Although the thermostats can be wired externally to a contactor, these are probably connected in series with the run windings. This is one of those deals that I would need to have in front of me to diagnose.
This diagram might help you better understand what your up against.
We had a fire several years ago that destroyed most of our schematics and diagrams of older motors, but I will look and see if I can find further info.
