Hi all,
I have put an extractor fan in my Motorhome ceiling and connected it to a/c motor speed controller to slow it down and quieten it for night time. I've looked at the output on a cheap LCD oscilloscope and its cutting into each sine wave which is making the motor have a noisy whine or buzz on low speed. It's a 40w 230vac 3 speed motor, maybe shaded pole, there's no run capacitor anyway.
Can anyone suggest a low pass filter circuit to block the noise? I've next to no experience with making inductors but fine soldering and using other components.
I'm an air conditioning engineer by trade but studied electronics when I was 16 and have remained a keen hobbiest ever since.
Thanks in advance
I have put an extractor fan in my Motorhome ceiling and connected it to a/c motor speed controller to slow it down and quieten it for night time. I've looked at the output on a cheap LCD oscilloscope and its cutting into each sine wave which is making the motor have a noisy whine or buzz on low speed. It's a 40w 230vac 3 speed motor, maybe shaded pole, there's no run capacitor anyway.
Can anyone suggest a low pass filter circuit to block the noise? I've next to no experience with making inductors but fine soldering and using other components.
I'm an air conditioning engineer by trade but studied electronics when I was 16 and have remained a keen hobbiest ever since.
Thanks in advance