First time user here...
I have a project that I am assigned at work. We manufacture customer inductors and transformers and part of the testing involves applying power, either AC or DC, at elevated temperatures. Some of the tests are completed during the night or weekends and we use timers to shut off the temp chambers but we do not have anyway to remotely remove the applied power. If we simply turn off the AC power supply, the feedback from the inductors in the temp chamber blows the output stage. If we interrupt the signal path, using a relay for example, then the output stage of the AC power supply is severely stressed. What I need to do is to find a way to ramp down the applied voltage over a period of time, say 60-90 seconds.
I was considering using a triac in a manner similar to a light dimmer circuit but instead of a rheostat, using a digital potentiometer in the RC circuit. My concern here is that we use a frequency range of 400Hz to 100KHz in our testing and the RC circuit may not provide enough phase shift for the entire frequency range.
I was also considering using a VCO to the trigger the triac and slowly ramp down the frequency but since the triac will not trigger at the same point on the sine wave each time the resulting ramp down signal will be very erratic and noisy.
One option would be to build a ramp down circuit for a smaller frequency range, for example 400Hz-1KHz, but I would like to have one, fit all circuit.
I have a project that I am assigned at work. We manufacture customer inductors and transformers and part of the testing involves applying power, either AC or DC, at elevated temperatures. Some of the tests are completed during the night or weekends and we use timers to shut off the temp chambers but we do not have anyway to remotely remove the applied power. If we simply turn off the AC power supply, the feedback from the inductors in the temp chamber blows the output stage. If we interrupt the signal path, using a relay for example, then the output stage of the AC power supply is severely stressed. What I need to do is to find a way to ramp down the applied voltage over a period of time, say 60-90 seconds.
I was considering using a triac in a manner similar to a light dimmer circuit but instead of a rheostat, using a digital potentiometer in the RC circuit. My concern here is that we use a frequency range of 400Hz to 100KHz in our testing and the RC circuit may not provide enough phase shift for the entire frequency range.
I was also considering using a VCO to the trigger the triac and slowly ramp down the frequency but since the triac will not trigger at the same point on the sine wave each time the resulting ramp down signal will be very erratic and noisy.
One option would be to build a ramp down circuit for a smaller frequency range, for example 400Hz-1KHz, but I would like to have one, fit all circuit.