AC Voltage Regulator

So I've been told to avoid the humming and to just be easier on inline fans overall, to use a caring rather than the cheap fan speed controllers like speedster. Caruso's ate AC voltage regulators. I see all kinds of different cheaper AC voltage regulators on eBay that ate much cheaper. But I don't think they do the same thing. Can anyone explain to me what a Variac actually does compared to Fan Speed controllers and what the cheapest way to accomplish what a Variac does without spending the $40 on one?

Cheaper Ones:
https://www.ebay.com/p/4000w-AC-110v-220v-SCR-Motor-Speed-Controller-Voltage-Regulator-Dimmer-Te474/4021973418?iid=232968580725

https://www.ebay.com/p/10000w-AC-220v-SCR-Speed-Controller-Motor-Electronic-Voltage-Regulator-US-Stock/15011211698?iid=142829347850

Variac:
https://www.ebay.com/itm/500VA-Variac-Transformer-5-Amp-Variac-Variable-Transformer-0-130-Volt-Output-BA/123378841684?epid=1061494821&hash=item1cb9f3b854:g:MeUAAOSw7yhbofDn

Probably should have put this in some other forum. Not sure which though...

Not sure what a 'Caring' is or familiar with that term. I would say do yourself and your fan a favor and get the variac. Those cheap fan controllers all use something like a SCR to clip the AC sine wave; effectively starting and stopping the motor every cycle and hence the buzzing and wear on your fans. The variac is basically a single coil that is center tapped and acts somewhat like a potentiometer to lower the voltage, you can read up on them as it has been quite sometime since school. Variac FTW!

buyyouabeer said:

Not sure what a 'Caring' is or familiar with that term. I would say do yourself and your fan a favor and get the variac. Those cheap fan controllers all use something like a SCR to clip the AC sine wave; effectively starting and stopping the motor every cycle and hence the buzzing and wear on your fans. The variac is basically a single coil that is center tapped and acts somewhat like a potentiometer to lower the voltage, you can read up on them as it has been quite sometime since school. Variac FTW!

Click to expand...

I edited my post to fix that typo. Thanks.

A variac is the best exhaust fan speed controller because it just lowers the A.C. voltage to your fan. It does not modify the sine wave in any way. But cheaper than a variac is to wire a 20" box fan (like from Walmart, Lowes or Home Depot) in SERIES with your exhaust fan using a duplex receptacle outlet. Then the voltage is split between the fans. They both end up getting lower voltage, slower air speed and very quiet.

WARNING: You would have to know a bit about wiring up a "duplex receptacle outlet" and cord for the wall to get it done.