Rheostat on Hatari 22" house fan

[bamboozled]

Hiya folks,

 

I just bought a big Hatari fan, a 22" that stands on a tripod and really lets it rip (can see it on Amazon here at about 10 x the price: https://www.amazon.com/Hatari-Industrial-Electric-Glossy-Hc-i22m1/dp/B01AZ94FVK). In fact, it's a little bit much and strangely the difference between the speeds 1, 2, and 3 is almost negligible (almost as if the slow speed was already almost the top speed). Well, I put a cheap rheostat on it that I had laying around and I was able to knock the speed down to the perfect level...and all was good. But the top of the motor housing got pretty hot and I started to think that perhaps this was not a good idea electrically (though the motor gets hot without the rheostat, too, but perhaps not as much) and so I've gone to searching on the internet where I've seen answers saying it's fine and answers saying don't do it. Some folks claim I need a different kind of thing-a-ma-jig to properly cut the current. Anyhow, does anyone with feet on the ground here in Thailand and knowledge of such things have any conclusive input? Can I use the rheostat? Do I need to purchase a "fan speed controller" (such as for a ceiling fan) or a different kind of switch? Or is there nothing to be done except be blown away? Thanks folks, cheers.....

[Crossy]

Did you really use a rheostat?

 

Looks like this:-

 

Value, rating?

 

Or did you use a lamp-dimmer type speed controller?

 

A proper fan controller isn't terribly expensive, but they can still make the motors buzz annoyingly.

 

You could try an x-rated capacitor in series with the fan (it's what most use for speed control anyway), try about 1.5uF to start with. If you pop the lid off the beast you should see the capacitor, try replacing it with one about 1/2 the value.

 

Note that if you did use a genuine rheostat it won't hurt the motor although both the motor and rheostat will get warm in operation.

[bamboozled]

Hi Crossy,

 

I thought a rheostat and lamp dimmer were the same thing but based on your question I guess not. I posted a pic below of what I used. As I said, I didn't notice anything amiss except the motor of the fan seemingly getting hotter than without using this dimmer box. Does that make sense? I did not notice any buzzing. Do you think I can carry on as is or am I risking damaging the fan motor? If I replace the capacitor....what is the outcome? Slower speeds on the fan?

 

Thanks for your help, very much appreciated. 

[Crossy]

OK, that looks like a triac speed controller.

 

Yes, the motor will run warmer using these (less airflow, more slip, odd waveform), if it's not getting excessively hot (too hot to touch, odd smells) it should be fine.

 

If you can find one of the capacitor based fan controllers (they are usually switched rather than continuously variable) that would be better.

 

Replacing the fan capacitor should run the fan slower, but since it's new I wouldn't do anything to invalidate the warranty.

[bamboozled]

Hi Crossy,

 

Something such as in the attached image? I can wire up something like that, sure. That little bit is not above my capacitor, um, I mean my capacity. Will this keep the motor cooler? Do I need to look for a particular rating with the switch?

 

Thanks again, cheers...

 

 

 

 

[Crossy]

Yeah, that's the beastie.

 

Because they add impedance (and maintain a nice sine wave) rather than chopping up the waveform into something horrible like the triac ones do, it should keep the motor cooler. It will still run warm because of the reduced cooling airflow but should be just fine.

 

They usually specify a Wattage range, make sure you get one that matches the fan, I can't quite read the label in your photo but it's 1xxW.

[bamboozled]

Excellent. I'm off to the switch store! Cheers, your help will keep me cool as a cucumber and safe, too.

 

Thanks!

[INDI12]

Im looking for 3 speed control switch as well. Any ideas where to find in chiang mai area? 

 

[bamboozled]

Just driving around you will pass many electrical shops, even around the moat. I'm sure they will have them. Home Pro or Global House probably also has them. I have not yet purchased one yet, however, but it's on my list.

 

[INDI12]

I will try the electric shop first near chiang mai gate where wuali rd meets moat. down wuali just behind 7-11 has alot of f gear in there.i need something that will handle at least  500 watts.

i put in a ceiling  whole house extraction fan. need some speed control.

[INDI12]

This what I have

wanted a 3 speed switch wall mount for it

is possible?

Whats needed?

Schematic shows can b wired forward or reverse 

 

 

Edited March 16, 2017 by INDI12
forgot pic

[INDI12]

[INDI12]

This what I have

wanted a 3 speed switch wall mount for it

is possible?

Whats needed?

Schematic shows can b wired forward or reverse 

 

 

[INDI12]

well tried 1 to 3 speed fan control with 1 box capacitor in it like one one in photo from other post. didnt work only work on high speed. med & low no workie... just turned off..

 

[Crossy]

Was it rated for a 1/3 horse (250W) motor?

 

Most indoor fans are 100W or so, so your capacitor would likely be way too small.

 

With a motor that size you'll be DIYing with assorted motor run capacitors. What value is the cap in your speed controller?

 

[INDI12]

hi                  yeah just...... 250 w

 

[Crossy]

1 minute ago, INDI12 said:

hi                  yeah just...... 250 w

 

Are you sure? It certainly does not say that anywhere on the image you posted. Did it say on the packing?

 

250WV is the working voltage of the capacitor, I would suggest finding a motor run capacitor of about 12uF and trying that just in series with the fan (don't bother with the switches). You can try different combinations of capacitors but please ensure they are 250V AC type.

[INDI12]

shop did have a transformer based four speed switch unit old style in a big metal case push button style. "lucky Misu" brand......  not sure that would work or not

 

 

[Crossy]

Just now, INDI12 said:

shop did have a transformer based four speed switch unit old style in a big metal case push button style. "lucky Misu" brand......  not sure that would work or not

 

It may well do the job, rating?

 

[INDI12]

thanks for reply crossy

was hoping to have a bit of control over speed.

 

[INDI12]

i think it was rated 1 amp ...

so a tad low?  240 watt

 

[Crossy]

The problem in your case is the size of the motor, a transformer based solution (variac) may well be the answer.

 

https://www.aliexpress.com/item/Household-tdgc2-single-phase-variac-1000w-0-250v-transtat/1408200249.html

 

Ideally you need a VVVF (Variable Voltage, Variable Frequency) drive, but they are not cheap ($200 or so).

[INDI12]

at that price i think i would run without speed control and let wifey moan a bit about fan not quiet enough......555

or get another fan. i got the fan i have now new for free so thought id use it.

maybe a different pitched blade?????

Ill look at the 300 baht transformer based 4 speed switch unit specs again.

[Crossy]

For 300 Baht I'd give it a go, it may get a bit warm mind, but it's not going to catch fire or anything like.

 

[Wirejerker]

17 hours ago, INDI12 said:

Ill look at the 300 baht transformer based 4 speed switch unit specs again.

The motor has dismal power factor so you will need to look at the VA rating.

220V x 3.3 amps = 726 VA

Simply any speed control needs to handle better than 3.3 as the current will increase as the speed drops. The transformer will make the pf worse but this most likley won't need to worry u