From the I.E.T. wiring Regulations forum for you. Have a look today. Either get a good quality sine wave output U.P.S., or a rotary converter with a sine wave output, or disconnect the fans during a short duration power cut. A petrol run generator may provine a pure sine wave output as well. Dimmer switches do not like the square wave output of cheap U.P.S. devices.


Bye,


Z.

Hello Clive


Thank you for your reply.


Suppose, i have such a UPS which have not providing a pure sine wave and i am using a coventional Dimmer too.  Is any special kind of Dimmer or related electronic device available in the market by which i could overcome the subject issue.


Other given solutions are costly.  Thank you.

To the best of my knowledge, there are no inexpensive devices that can replace a triac-controlled (phase control) dimmer in this application.


Most likely, you would need to consider replacing the phase control device with a pulsed controller using more expensive components. Heat sinking may also be an issue, as would ensuring that the switching frequencies of these don't align with the fundamental or harmonics of the UPS switching frequency. Even then, there's perhaps no guarantee that it would work.


Cheaper UPS are designed to feed a rectifier and reservoir capacitor in a switched mode power supply for information technology and similar equipment, hence their inability to feed the more complex AC power control applications.