4 ceiling fans on 1 fan speed control??

[sw_ross]

I have a commercial office building that has 4 ceiling fans 35' off the ground (in an Atrium type open space) that need to be changed out. They were originally installed in the early 80's, I was told!? 2 of the 4 don't work, they want all 4 changed out.

It appears that all 4 fans are controlled by 1 speed controller located in a utility room.

I need to figure out what type of fan I can install that can be controlled from 1 speed controller?
I haven't had good luck in the past by having more than 1 fan controlled by a single speed controller?!

Any advise or suggestions?

I can't afford to have issues down the road and have to rent a lift a second time to change something because I didn't do my homework now!!

Thanks for suggestions or advice!
Sky

 

[Fulthrotl]

I need to figure out what type of fan I can install that can be controlled from 1 speed controller?
I haven't had good luck in the past by having more than 1 fan controlled by a single speed controller?!

Any advise or suggestions?

of course we have suggestions.....

 

[sw_ross]

Ha!

Ha!

I've seen those in a restaraunt near where I'm at! That's crazy! 4 fans operated by 1 motor! I guess a single speed controller would work fine there!?

That's not exactly the solution that I was looking for, especially when it's 35' off the ground!!

 

[brantmacga]

4 ceiling fans on 1 fan speed control??

P&S Titan fan speed control comes in 6A and 12A load.

Typical ceiling fan motor will be 70w on high speed.


Sent from my iPhone using Tapatalk

 

[sw_ross]

Low speed setting - 2nd fan wouldn't turn

Low speed setting - 2nd fan wouldn't turn

The last time I installed 2 fans that operated off 1 speed control was a shop building that had hydronic heat in the floor, and wanted the ability to circulate the warm air in the winter time.

We had 1 switch leg from the switch location to the first fan, then interconnect from fan to fan. Using the speed controller that came with the fans, at High speed the first fan would spin noticeably faster than the second fan. As you turned the controller to lower speeds, the first fan would operate as expected. The second fan would be noticeably slower, and at Low speed setting the second fan wouldn't turn, just humm!

 

[kwired]

P&S Titan fan speed control comes in 6A and 12A load.

Typical ceiling fan motor will be 70w on high speed.


Sent from my iPhone using Tapatalk

Your typical ceiling fan motor is a PSC motor. All most electronic controllers do is shave the peaks off the voltage wave, causing the motor to produce less torque and the result is less speed. How many fans can be run from one controller is primarily determined by the rating of the controller. A controller for a single fan may only have a 1.5 amp rating, while one for 5 fans maybe a 5 or 6 amp rating.

The last time I installed 2 fans that operated off 1 speed control was a shop building that had hydronic heat in the floor, and wanted the ability to circulate the warm air in the winter time.

We had 1 switch leg from the switch location to the first fan, then interconnect from fan to fan. Using the speed controller that came with the fans, at High speed the first fan would spin noticeably faster than the second fan. As you turned the controller to lower speeds, the first fan would operate as expected. The second fan would be noticeably slower, and at Low speed setting the second fan wouldn't turn, just humm!

I think you had other issues besides mismatched controller to number of fans. True the furthest fan would see more voltage drop, but you would need a very long run of conductor for it to be a visually noticeable difference.

 

[mwm1752]

you could control any dim switch remote as long as the configuration is set -- kinda like the type of people (crooks) the drive down a street pressing remote garage door opener to see which doors open. no worries on current or circuitry

 

[kwired]

Your typical ceiling fan motor is a PSC motor. All most electronic controllers do is shave the peaks off the voltage wave, causing the motor to produce less torque and the result is less speed. How many fans can be run from one controller is primarily determined by the rating of the controller. A controller for a single fan may only have a 1.5 amp rating, while one for 5 fans maybe a 5 or 6 amp rating.

I probably was't entirely correct with "shave the peaks off", but was still close enough in that they shave off some part of the wave, leaving the motor with less input power and ultimately producing less output power.

 

[Jraef]

I probably was't entirely correct with "shave the peaks off", but was still close enough in that they shave off some part of the wave, leaving the motor with less input power and ultimately producing less output power.

You're not that far off actually. It's not that the peaks are "shaved", the triac just delays when it turns on in each cycle so that only a portion of each sine wave gets through, but EFFECTIVELY the RMS peaks end up lower. Then what that does is reduce the TORQUE that the motor can produce, which, in a paddle fan, ultimately reduces the speed.

Low speed setting - 2nd fan wouldn't turn
The last time I installed 2 fans that operated off 1 speed control was a shop building that had hydronic heat in the floor, and wanted the ability to circulate the warm air in the winter time.

We had 1 switch leg from the switch location to the first fan, then interconnect from fan to fan. Using the speed controller that came with the fans, at High speed the first fan would spin noticeably faster than the second fan. As you turned the controller to lower speeds, the first fan would operate as expected. The second fan would be noticeably slower, and at Low speed setting the second fan wouldn't turn, just humm!

My suspicion here is that you may have inadvertently wired the fans in series, not parallel, so the first fan was dropping the voltage to the second fan even further, so when you went to low speed, the voltage getting through to the 2nd fan was so low that it would not produce enough torque to even turn itself. For multiple fans, you MUST wire them in parallel.

So as was said, just look at the rating of the fans and make sure the speed controller is rated for 4x the fan power, more is better. If, because the fans are 35' in the air so are larger than typical house fans, the total for all 4 fans exceeds the largest size speed controller you can get, you may need to go a different direction. There are a couple of mfrs of VFDs that will run single phase MOTORS, as long as the motors are PSC or Shaded Pole. As said, most paddle fans are PSC motors, so that would work. Rather than go down that path needlessly, find out what the motors are rated for and if it's too much, report back and we'll delve into that option.

 

[sw_ross]

Looked further into situation...

Looked further into situation...

I went back to look further into the existing setup today,

Here's a pic of one of the 4 fans. They were operating today! When I asked the maintenance guy about it, he said that when he pushes them at full speed you can hear the bearings grinding in 2 of the 4 fans, so he pays attention to how long they're on and how fast he has them set for.

I looked at the speed control switch,


When I had the fans turned on high, my clamp meter was only registering 0.5 amps?! that seems a little low for what I was expecting? Not sure why? The label on the speed control switch says it's rated for 3.0 amps.

 

[Dennis Alwon]

There may be some speed control center where you can vary the speed however we never hook up a speed control switch to more than one fan. In a residence the only speed controller that words is a variable one and they make the fans hum terribly. I don't know of a speed control that would work 4 fans

 

[GoldDigger]

There may be some speed control center where you can vary the speed however we never hook up a speed control switch to more than one fan. In a residence the only speed controller that words is a variable one and they make the fans hum terribly. I don't know of a speed control that would work 4 fans

Do you experience bad hum even with the built-in remote speed controller that some fans have? I would think that such a unit would be optimized to that fan service.

 

[kwired]

Does your fans have three speed switch on the fan? If so make sure they all are set on "high" setting if you are going to use a wall speed controller.

Dennis there are speed controllers rated for multiple fans. They are not so common in dwellings as you seldom have several fans on same control in a dwelling. Occasionally you may have two but usually no more then that.

Commercial fans however quite often are connected with more then one on a controller. I've even done poultry barns with maybe 8-10 fans on a single controller - those were basically a washdown rated commercial fan - but the motor is still nearly identical in it's base design as a typical residential fan.

If I wanted to run say 15 -20 amps worth of these fans, I could use a fan controller that is typically used for variable speed ventilation fans, as those controllers come in sizes that can handle that kind of load. Such controllers that I commonly run into with that kind of load capacity are more typical for livestock buildings, but again you are still controlling PSC motors, so the basics are the same and it will work.

 

[sw_ross]

The existing speed controller is an Emerson sw-81, rated for 3 amps. Nameplate say's that it's for use with Emerson fans only (CYA?). I looked up the online info for this controller, it's labeled as an "Industrial" fan speed control. The PDF for this controller also says it's for use with Emerson fans only as well. I assume the existing fans are also Emerson ?

What brand of speed controller do most of you use? What brand of fan are you controlling with that controller?

 

[kwired]

The existing speed controller is an Emerson sw-81, rated for 3 amps. Nameplate say's that it's for use with Emerson fans only (CYA?). I looked up the online info for this controller, it's labeled as an "Industrial" fan speed control. The PDF for this controller also says it's for use with Emerson fans only as well. I assume the existing fans are also Emerson ?

What brand of speed controller do most of you use? What brand of fan are you controlling with that controller?

I believe it is a CYA type of thing more then anything else. For one thing the manufacturer likely never tested the fan or the controller with any competitors models, they likely will work when mismatched but they won't guarantee any performance levels. Sort of no different then installing a Homeline breaker in a Siemens panel.

I know Emerson has multi-fan controllers as I am fairly certain I have used them before.

I have also used Lutron fan controllers - majority if not all I have used were for a single fan only - but AFAIK Lutron does not make fans so they are always used with fans made by others, for whatever that info may be worth.

 

[rippledipple]

fans

fans

I have a commercial office building that has 4 ceiling fans 35' off the ground (in an Atrium type open space) that need to be changed out. They were originally installed in the early 80's, I was told!? 2 of the 4 don't work, they want all 4 changed out.

It appears that all 4 fans are controlled by 1 speed controller located in a utility room.

I need to figure out what type of fan I can install that can be controlled from 1 speed controller?
I haven't had good luck in the past by having more than 1 fan controlled by a single speed controller?!

Any advise or suggestions?

I can't afford to have issues down the road and have to rent a lift a second time to change something because I didn't do my homework now!!

Thanks for suggestions or advice!
Sky

Won't work, you need to run 3 more sw legs and add 3 controls

 

[kwired]

The existing speed controller is an Emerson sw-81, rated for 3 amps. Nameplate say's that it's for use with Emerson fans only (CYA?). I looked up the online info for this controller, it's labeled as an "Industrial" fan speed control. The PDF for this controller also says it's for use with Emerson fans only as well. I assume the existing fans are also Emerson ?

What brand of speed controller do most of you use? What brand of fan are you controlling with that controller?

Emerson SW-82 is similar control but rated for 12 amps. It should have no trouble with 4 fans. Sometimes those infinite type controllers make the fan motor hum louder but you mentioned they are 35 feet up - so it may not be all that noticeable.

 

[sw_ross]

Rippledipple,
ideally I wouldn't have set it up the way it is! It would be great if there was an individual control for each fan located in that janitors room, but there isn't! Bummer! Everything is finished out, and I have to work with what is there! The current setup has worked well since the early 80's, I just need to find adequate replacements for what they have now that's worn out!

Kwired,
Thanks for the suggestion! I'll research out the sw-82 controller!

 

[Dennis Alwon]

Do you experience bad hum even with the built-in remote speed controller that some fans have? I would think that such a unit would be optimized to that fan service.

I have never usede a fan with built in controls for speed. There is, as you know, a difference between a speed selector control and a variable speed control. The variables are the only ones I have seen rated for more than one fan and they are the ones that cause hums. The selector (2 OR 3 SPEEDS) speed controllers are fine but will only do one fan

 

[kwired]

I have never usede a fan with built in controls for speed. There is, as you know, a difference between a speed selector control and a variable speed control. The variables are the only ones I have seen rated for more than one fan and they are the ones that cause hums. The selector (2 OR 3 SPEEDS) speed controllers are fine but will only do one fan

Emerson had one controller (selector type) that was rated for 2 fans, when I was looking up information for previous posts in this thread.

Otherwise it has been my observation as well that the variable speed types usually cause more motor hum then a fixed speed selection type, but as I mentioned to OP that with his fans being 35 feet above the floor any noise may not be all that noticeable in this application.