🎛️ Enhanced Adjustable Reversing Controller by RioRand Review

I bought this to install in a Heng's Industry Vortex fan in my RV to add variable speed capability to it. Unfortunately, the speed controller causes excessive fan motor hum at any speed other than full and off. The fan itself is a bit noisy, so the speed can be reduced a bit before the howling noise drowns out the fan noise. I've tried twisting the wires and putting a ferrite toroid on the wires to muffle the noise, but that didn't work. The speed controller isn't a waste of money (it's pretty…

So I bought this to control the fan in my RV, it's over the main bed. It seemed like a great idea, being reversible (to bring fresh air straight in) and variable speed (to create the faintest exhaust breeze while you sleep). It works as described: The reversing switch is a three-position switch: forward, off, reverse. ; The rheostat slows the motor to a complete stop or starts it at full speed. The product gets five stars for functionality. Here's where it falls apart: NOISE - three to four…

I may have a defective unit but I seriously doubt it because I bought two of them. It looks like they've updated their PCB layout since then, but not much to be honest. I want to be very clear: the components used have no chance of using a PWM frequency of 500 kHz. All the through capacitors they use have a capacitance of 0.1uF, resulting in an oscillation frequency of 50+Hz, I've seen 54Hz. In fact, I wouldn't call this device a PWM controller. They use a quad op-amp (LM324) to essentially…