RMO-M Series - DV Power Motor Winding Ohmmeter

The motor/generator winding resistance test is used to identify open windings, shorts between two windings, short to grounds, connection mistakes, or shorted turns. This non-invasive test of winding resistance helps to pinpoint problems regarding windings in the stator or rotor part of an electrical machine. Additionally, motor winding ohmmeter has the capability of performing heat run test which will show a change in windings resistance with an increase of temperature. This is especially useful for testing rotating machines after manufacturing.

RMO-M rotating machine winding ohmmeter is designed as an ideal aid in the preventive maintenance of electrical motors and generators. They are powerful (up to 50 A for RMO50M and up to 100 A for RMO100M), portable (8 kg), and generate DC current which is completely ripple-free. This makes measurement very precise with 0,1% accuracy. Windings problems that can be detected using RMO-M instruments are:

• Broken winding (open winding);
• Turn-to-turn short;
• Phase-to-phase short;
• Bad solder joints between the windings;
• Power circuit problems.

Three voltage channels make measurement very easy since it is possible to obtain a value of all three winding resistances in one measurement. The three-channel measurement option significantly speeds up the measurement process and reduces the total testing time.

Besides the windings, a resistance test can also provide valuable information about the power circuit condition. The power circuit refers to circuit breakers, fuses, disconnecting switches, conductors, etc. placed in the control box or local panel and connected to the motor/generator. High resistance in the power circuit can be a result of:

• Corroded terminals;
• Corroded contacts;
• Malfunction in the operation of circuit breakers or disconnecting switches;
• Loosen cables;
• Loosen bus bars;
• Open circuit.

DV-Win application software enables control and monitoring of the test process steps, as well as saving and analyzing the results on a PC. It provides a test report, arranged in a selectable form as an Excel spreadsheet, PDF, Word, or ASCII format. The standard interface is USB while RS232 is optional.

Write a review

Your Name:


Your Review: Note: HTML is not translated!

Rating: Bad           Good

Enter the code in the box below: