Regulating generator voltage

      Dealing with voltage control and wiring for generators. January 31, 2001

I have just installed a used 375 KVA generator at my shop. Will I need to do something to control the voltage? The tag says it will produce 480 volts/350 amps at 1800 RPMs. It is hooked right to the breaker cabinet now. Can I wire it right to my moulder? I installed a governor on the engine and set it at 1800.

Forum Responses
The engine governor should maintain the voltage at the rated speed. The generator should already have a voltage regulator in the control circuit. You can install an over-under voltage sensor.

You cannot run the generator together with the local net, just separated (unless you always provide a synchronizing). Be sure that the main is always switched off when you are going to run the generator.

It depends on the way the generator is set up to operate. Get a cheap voltage meter and read the voltage output. The governor is designed to automatically speed up the generator, or slow it down, depending on load demand. Be careful with the test leads and don't get shocked.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Generators are controlled two ways at the same time. The voltage is controlled electrically via the power sent to the rotating field. The frequency, cycles per second, Hertz (usually) 60hz. is determinded by the rotational speed of the prime mover (engine). 1800 rpm is this case. The governor controls the engine speed and is supposed to hold it to 1800 rpm or 60 hz regardless of the load. The fuel consumption goes up the more load you apply to the generator but the speed is suppposed to remain constant.

Always consult a qualified electrician. Previous comments about a disconnect and the governor are usable information. You obviously don't want to feed into the electrical distribution line of the local utility, so a disconnect from main panel is appropriate. The local utility will have requirements for this type of back-up generator setup. Also, conact the utility to insure their system can handle your new load - if you are at the end of a circuit, you could experience poor voltage problems.

Comment from contributor D:
If connecting a generator to a mains fuse board then you must use a mechanically and electrically interlocked double contactor to switch over automatically or a double pole two position switch. In this case if you run the generator during a power failure there is no chance of voltage appearing on the lines out of the building and electrocuting the people re-connecting the power. It is always advisable to use a voltage regulator where you have sensitive devices such as computers and electronics.

Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?

Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Dust Collection, Safety, Plant Management

  • KnowledgeBase: Dust Collection, Safety, Plant Management: General

  • KnowledgeBase: Solid Wood Machining

  • KnowledgeBase: Solid Wood Machining: General

  • KnowledgeBase: Solid Wood Machining: Setup and Maintenance

  • KnowledgeBase: Woodworking Miscellaneous

  • KnowledgeBase: Knowledge Base

    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.

    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2021 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB

  • WOODWEB - the leading resource for professional woodworkers

      Home » Knowledge Base » Knowledge Base Article