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Electric Motors/115 /230 volt motor


QUESTION: I have 115 / 230 volt motor for table saw.  It can be wired for either 115 volt or 230 volt. I have run it at 115 volt but works better at 230 volt.  I've changed the motor wiring configuration to run at 230 volt, which has worked in another location, but won't work in current location.  I tested the 230 volt power source and am getting 119 volt on each side of the 230 outlet. Tested current at motor, and get same readings.  Motor will not operate at 230 Volt with this power source, can you offer reason why? Motor was tested at electrical shop, at 230 volt, and ran fine.

ANSWER: The power supply may be connected to neutral on one side and hot on the other prong.
You need the 2 HOT's on each side of the 230V receptacle. Then the middle pi is neutral and the 4th pin is ground. Very similar to a stove or dryer plug.

then motor should work fine.

---------- FOLLOW-UP ----------

QUESTION: The receptacle has one hot on each side, no neutral, and a ground as the middle. The wiring diagram for 230 volt on motor shows two hot lines and ground.  Motor wire combinations go to the two hot lines and have several other wires taped. This connection configuration has worked with other 230 volt power source, in a different location, but won't work at current location? Both sides of the outlet test at 119 volts, at the motor. If the motor operates when wired for 115 volts, shouldn't it work when rewired for 230 volts? Thx

It should work at the 230V conn. if the wiring is configured correctly, which it seems to be because it runs in a different location.
The 119V you are measuring, is it between each HOT to neutral?

Measure the voltage on the 2 HOT cables which are connected to the motor leads. It should read 230V as well.
If it reads only 119V, then thats what the motor sees also, and wont run or wont accelerate to speed under load.

If the voltage is 230v at the motor leads then check the starting capacitor

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Harcharan Singh Diocee


Electric motor winding redesign, AC and DC. Troubleshooting, motors controls generators. Vibration analysis, dynamic balancing, root cause analysis: electrical and mechanical.


thirty five years electro-mechanical and Senior Management


Journeyman Motor Rewinder, Millwright, Industrial Electrician, Vibration Analyst level II. Certified Electrical Technician ASTTBC, FSR Class B, in BC. Laser alignment specialist. Marine machinery repairs. Business Management Certificate. Last 19 yrs as Plant Manager

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