Wiring The Xpelair Wac1 Fan Speed Controller (transformer Based)?

[Guest The Sheriff]

Ouch sounds like ur gonna be having fun juggling all that about , wonder if anyone else is havening issues with the wac1 ? Im sure more on here use them .

[h4z3]

Ouch sounds like ur gonna be having fun juggling all that about , wonder if anyone else is havening issues with the wac1 ? Im sure more on here use them .

Hey TheSheriff . Hope all is well mate.

I wish I had bought a variac (variable transformer) instead of a 5-step down transformer (the type WAC1 is) for this RVK 125A1 intake fan. It would be better to be able to accurately adjust the speed to the exact desired level/step.Fixed steps are not as good imo ..

Anyhow the WAC1 is a good fan controller and quite cheap , great choice for value , I hope it works 'better' with a stronger fan like my RVK 150A1 extractor.The best thing is I get no buzz at all at low settings. One thing for potential buyers of the WAC1 , from my personal experience with it : I wouldn't reccomend it for the RVK 125 cause it seems that the voltage steps at the different speed settings are not the ones you 'really need'..

Step 4 is OK but step 3 should provide more watts , there is a huge gap/difference in airflow between the 3 and 4 .. At 4 fan is still very 'noisy'/'loud' and too much airflow ..at 3 it is too 'weak' and way too 'silent'...It seems an intermediate step is what one really 'needs'.

..steps 1-2 are pretty much useless with this Fan (RVK 125A1).

Like I said I 'll wire my bigger extractor fan (RVK 150A1) and try both fans in my room see how it goes and keep you updated.

I hope I don't have to do modifications and 'create' an intermediate step myself , between 3 and 4 ...cause unfortunately I suck at electrical stuff..

Perhaps I might have to go with the alternative option to use some sort of resistance to lower the voltage a bit and run the WAC1 at speed 4 ?

like scraglor advised:

you could link two of the output taps together, essentially reducing the transformer to a 4 step, although i don't advise it as i haven't done it myself, so cannot predict the outcome, or just an inline resistor if you're only trying to shave off a small amount of voltage, all a bit of a pain in the arse though

What exactly would I need to buy & do this? Would it be as simple as using a resistance 'after' the WAC1 output to get some of the power to be converted into heat at the resistance?Why would this be a real difficult thing to do?

Edited December 9, 2007 by h4z3

[scraglor]

basically yeah, just stick a resistor in series with the fan input, not really a pain if you're only ever gonna have the fan running at the same setting all the time, just if you ever want to change the fan settings it will effect all the settings, and on higher settings you could burn the resistor out if it's not the right power rating, just have to work out what resistor you'd need which is a bit of a pain in the arse as motor impedances change as the voltage changes, and without being able to measure the current drawn at the lower voltage i can't work out the impedance, so i'd need you to run the fan at speed four through an ammeter and also at three and check the current to do it properly.

although you could just try different resistances until you get what you want

Edited December 9, 2007 by scraglor

[scraglor]

also check the voltage on those two unused taps, never know, might be the right voltage

[h4z3]

Hey scraglor

Thanx again for the quick reply.

I think I first need to get a Amp-meter/Volt-meter whatever I will decide to do.

Well I will get one and measure things at 4 and 3 and let you guys know.

[scraglor]

yeah, just a shame i don't have one, i could sort this out in 10 minutes if i had it in front of me

[h4z3]

yeah, just a shame i don't have one, i could sort this out in 10 minutes if i had it in front of me

..I should be the one to use the word shame cause it a shame I 've forgot all things about electricity etc ..I was very goot at school at Physics ..too much weed and zero practice after I finished helped forget all about it . :wink:

Thanx for all your help so far man I really apreciate it.

[h4z3]

Hey whazzup thanx for the screenshot and explenation

Exactly what thought the prob was being caused.

Do you think I will have similar problems with my RVK 150 A1 ??

Edited December 9, 2007 by h4z3

[h4z3]

Thanx for the super fast reply :wink:

That was my initial thought..i believed the RVK 150 A1 would respond better to the voltage drop as it has quite 'similar construction size' and same R.p.m. at full speed to the RVK 125 A1...which means that the main difference is the width of the blades and their design.At full speed it runs at double wattage/power than the rvk 125 A1 so I thought that I wouldnt have similar probs at low wattage. :wink:

Do you believe it will be the best/easiest option to use a resistance to drop the power a bit or should I try to modify the tranny to get an intermediate step between 3-4 for the 125A1 rvk fan?

Edited December 9, 2007 by h4z3

[h4z3]

You mean use the WAC1 to get to setting 4 and also use the rheostat (behind or after the Wac1 ??) to go a bit down?

Or straight rheostat?

Theoretically the rheostat might cause some buzz if I understand things correctly ..or perhaps it only causes buzz to the fan if you go way too low.

Could you please advise me what type of rheostat I should get , model/brand and 'size'?

Edited December 9, 2007 by h4z3

[scraglor]

no buzz mate, its just a variable resistor, so jst drops voltage, not like a triac, get one that's rated for 30watts and your well within limits then just wire it onto the output, dunno why i didn't just say that earlier, whazzups obviously way more on the ball than me! :wink:

[h4z3]

no buzz mate, its just a variable resistor, so jst drops voltage, not like a triac, get one that's rated for 30watts and your well within limits then just wire it onto the output, dunno why i didn't just say that earlier, whazzups obviously way more on the ball than me!

Thanx scraglor. One thing I still don't understand:

What exactly is the difference between a variable resistor and a variable transformer as far as RVK fan speed controlling is concerned??

The only thing I can think of is that with the resistor .. you always use the same power as the fan would use at full speed but

the 'resistance wire' converts the electricity the fan doesn't use into heat.

The transformer doesnt do that if I understand things correctly ..it just 'forces' the fan to suck the desired ,at each step, power from the mains so you use less power at low speeds, right?

Edited December 9, 2007 by h4z3

[h4z3]

long time since I had accurately to calculate anything AC really . Would have to dive into the books but in any case it's important to house it properly, as it is under high voltage. Also if you are ok with speed 4 but want to get a bit lower then that, use it only on the 160 volts output to regulate that (so between your transformer and your selection switch, as you only regulate the 160V output. It dissipates less energy at lower voltage / currents.

I wonder if you are just not better off with a 150L and use this as an inlet fan

Thanx pal , So you say use the rheostat (variable resistor) after the WAC1 controller and before the fan.

I have bought a 150A1 and an 125A1 so thats what I ve got now.

I want to use the 150A1 as extractor at speed 3 (with my second WAC1) cause I only have a 200m3/hrCan CarbonFilter and at speed 3 the RVK 150A1 extractor should provide 'exact' airflow to get total odor elimination with this CAN Carbon Filter. Theoretically if I used the 150A1 at higher speed it would blow air too quickly to get correct contact time with the carbon in the CanFilter = no total odor elimination/filtration.

The other RVK , the 125A1 Intake fan , I have 'problems',..is be too weak at 3 and is too much at 4.So I will most probably use a rheostat to do the job.

Any rheostat brands/models you 'd advise me to buy?

Edited December 10, 2007 by h4z3

[h4z3]

Personally in your situation I would have taken a larger filter and put the 125A on 4. It's always nice to have some reserve.

You are right , I know I should have bought a larger filter , but now I have to work with what I got.

if you put the rheostat between the controller and the fan it will work on every position of the controller. If you just want it to work on 3 or 4 you got to hook it up internally between the transformer and the selection switch on the front panel.

I wouldnt mind that actually as I will run the fans at constant speed at all-times.

BTW I have bought 2 WAC1 controllers so I will use the one at RVK 150 A1 extractor fan to set it at speed 3 .

The second WAC1 will be used for the intake 125 A1 to set it at speed 3 or most probably 4 to get descent airflow.

For this fan I will most probably use a rheostat to go a bit lower from speed 4 but higher that speed 3.

But why not buy a low wattage halogen dimmer for a few quid and use that one for the intake fan? The 125A is fairly quiet, would be a much easier solution. You are still using this controller for the 150.

The cheap low wattage halogen dimmers, are rheostat based right?

So if I get one I could use it to dim the power that goes out of the WAC1 just a bit? Or I would have to use it standalone with the fan (no WAC1)?

Edited December 10, 2007 by h4z3

[Rastajedi]

Hey whazzup thanx for the screenshot and explenation

Exactly what thought the prob was being caused.

Do you think I will have similar problems with my RVK 150 A1 ??

nope. this is only with the very small fans. Here is the 150A diagram

that is such a relief, thought i was going back to the drawing board for the fourth time, great info whazzup