You are here:

Electric Motors/install fwd rev switch on 3 wire 240v motor

Advertisement


Question
I have a milling machine that I had to replace the fwd rev switch but being a very old machine I couldn't get the same switch. The motor has 3 wires coming out of it a capacitor and is 1 phase 240v. I have tried connecting this switch a number of different ways and I can get it to run in one or the other direction but when I switch to opposite direction the motor tries to run but just sits there and hums until the overload trips out. one direction when it runs reads 240v opposite direction that hums reads 190v. I am at a complete lost any help would be greatly appreciated.

Answer
dr
dr  
see attached dwg which is for 6 leads.
your motor has 3. 1, 4 and 5
8 is internally connected to 2 and 3.

So follow the schematic for high voltage. with 1,4 5

You have identify which is 5 as that is the start winding which is interchanged with 1 and 4 which are the 2 run windings at 230V.

Electric Motors

All Answers


Answers by Expert:


Ask Experts

Volunteer


Harcharan Singh Diocee

Expertise

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

Experience

thirty five years electro-mechanical and Senior Management

Organizations
EASA, CSA, ASTTBC, FSR

Education/Credentials
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

©2016 About.com. All rights reserved.