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1700 cfm 12" 4.1 amp in line fan speed controller?

P

p0opstlnksal0t

Active member
Anyone have any ideas what fan speed controller I need? I've used the cheap rheostat versions and they just can't supply the amperage. I bought a 5 amp variac and it blows the 5 amp fuse on startup. I tried a 6 amp fuse and half the time it will blow that. When it doesn't blow it and I dim the voltage do around 78 volts everything runs OK for a few minutes then the fan shuts down due to the thermal overload protection and takes about an hour to cool down before I can plug it back in and have it work again.... not sure what I should try next?
 
P

p0opstlnksal0t

Active member
Ya that's what my variac is but it's still not working... properly. When I dial down from the originAL speed it's like the fan overheats and thermal safety kicks on. Maybe I should call hydrofarm. The description of the fan said it was speed controllable
 
P

p0opstlnksal0t

Active member
Looks like this
 

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W

watts

ohms
Veteran
Get the 10 amp variac. I believe that is the next size up from the 5 amp.

You want the amp rating to be at least 1.5x what the rating of your fan is. So if your fan is rated for 4 amps, it will have a surge of 6 amps on start up. Never lower the speed of a fan below 50% of its rated speed. This may cause the fan to overheat.
 
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p0opstlnksal0t

Active member
The problem is the lower voltage to dim the fan is causing the fans own thermal overload to kick on. It's supposed to be speed controllable but even when I don't pop a fuse in the varia and it runs at about 65% voltage around 75 volts the fan heats up and kicks off. Does a vfd lower voltage in the same manner?
 
Andyo

Andyo

Active member
Veteran
7 amp FASEC-33

7 amp FASEC-33

http://www.kaeltetechnik-shop.at/Fan-speed-control-FASEC-33-Eliwell
i ran scroll fans and duct fans off these the 7 amp rated 220/240 v
rate of increase per deg c controllable max min speed set ect
1x 800 cu/ft/min in another same out,easy to control negative pressure with settings

Thing is the fan i clearly remember 800 cu/ft/min drawing only 1.2 amps 220 v
You must have resistance or your on 110 V
 
W

watts

ohms
Veteran
Maybe it is the fan then. I am using an 8" Hurricane inline fan with a 3 amp variac. It works great.
 
P

p0opstlnksal0t

Active member
It has to be the fan because the thermal overload appear's to kick on if it's dimmed down the 78v or less after maybe 10 mins. I know a bigger varia would cure the fuse blow issue but I don't think it would cure the thermal issue with the lower voltage and higher amperage.
 
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