EX ELECTRONIX Express Variable Transformer, 300 VAC Max, 0-130V Output, 3 Amp

I bought a cheap one of the cheaper "Active Air" fan speed controllers for my 4" in line fan. Although the fan speed controller worked as advertised, I could tell the fan motor was under some strain. The fan struggled to start up if the speed was dialed down, and operated with a noticeable "buzz" or electrical hum. I did some research and saw that the in-line fans operate much better with a Variac variable transformer. Wow, what a difference this unit makes. My fan now starts slow and smooth, and runs with no strain on the motor at all. No "Buzz" no electrical hum. The only sound made is the air moving through the duct work. The volt meter on the front is an added bonus as well. I can tell exactly how my fan is doing at a glance.

I bought this to control the speed on one 6 inch inline fan. It has been running for 24 hours per day at just under 50%. I have not seen any issues with the variac, It is not even warm to the touch.The fan is not laboring or making any unusual sounds. I was unsure before purchasing, that it was the right choice for my application after using another type fan speed controller that failed. So far it has been flawless and would recommend to any one wanting to slow the speed of a fan. I have not tried to use it controlling two fans as the rating is 3 amps. If I purchase another it would be a larger amp rating.

I used this one time, it was then knocked off of a 2 1/2 foot shelf and ceased to function. It works as advertised, just not very sturdy.

First, I bought a ventech 4" inline fan combo for a 3x3 tent. When I hung it and turned on, it was way too strong for this size area. I thought at first was my only option was adding a speedster type fan controller. Just by the reviews for those you can tell they're not really made to work properly for inline fans. I'm so glad I stumbled on this item because when I hooked it up it worked perfectly. I slowly dialed it from slow speed up and at first I couldn't tell the fan was on until I felt the air coming out. I settled on a speed that I can tell is moving enough air in and out and I still can barely hear the fan. No motor hum, just smooth running. This is the best speed control device for inline fans.

Works just fine with a Lasko 20" Weathershield box fan. Fan goes down to about 40V and makes no noise at all. I'm planning on leaving the fan running 24/7. Mine didn't look like the picture (seller=Amazon.com) but the specs were the same. They've perhaps changed designs slightly. I opened this thing up to inspect quality, and although out of the box it has a strong plastic off-gassing smell, I didn't notice any issues with construction. My knob came installed at a tilted angle, but I didn't really care. Just a heads up, this thing is decently heavy for its size since it has a giant piece of steel/iron in it. I keep my reviews up to date, if you don't see any updates here then it means that from the date of this review to present I didn't have any issues.

didn't immediately explode and controls my fan without adding any operating noise. Build quality is OK to questionable; i'll be reading some of the other reviews to see if there's anything I can do to improve this safety wise. the manual they send you with the device is a complete joke. It seems like it was written in a different language then fed through some kind of bad automatic English translator. Here's an excerpt: "the voltage regulator should be kept clean, without any blob water, smeary inside, and close it and clean the dust regularly" the most unsettling thing is I can't understand what any of these instructions from the manufacturer are trying to tell me. It's as good as if there wasn't a manual (which might be illegal, hence the half-assed attempt).

This baby is great. I'm running a 6" inline fan with it and this thing throttles it down to next to no RPMs with no hum. Saves money and sound. After dialing in the speed I needed to keep temps and humidity where I wanted it, I really do need to place my hand on the fan to insure its on. My ballast fan is louder. This controller stays cool, mine didn't "smoke" or "smell". Glad I got this instead of a cheaper inferior speed controller. My tomatoes are important to me so the question is how important your crops are and how much you'll spend to keep your gear in good shape. As a side note I contacted the fan manufacture and they suggested I run this controller full blast for 72 hours in order to break in the new fan I bought with this controller. I assumed they knew what they were talking about.

This works better than I expected for the price. It is poorly grounded, has some really poor connections, super cheap excess or IES, and really needs a digital gauge but that hasn't stopped it from working well in the lab. I took it apart and fixed some of the more glaring design flaws and for the price it has been a really good Variac for bench work. Its still working great.

We installed a fan to bring warm air down to the very cold basement. This controller allowed the fan to be turned down so it is quieter and without any other noises. A cheaper one made the fan hum or whistle. Definitely recommend this product. It's worth the extra money.

Works well to control the speed of an electric fan in our home. The voltage knob adjusts very smoothly. Because it is rated at only 3 amps, I would not use this for anything requiring higher power.

Usefull and a nice tool to have