Ok, this isnt exactly about a hotrod. but it does pertain to my paint booth, which paints hotrods.
I cannot find anyone with the knowledge to help with this question.
How do i make my exhaust motor on my paint booth variable speed?
Here is some of the info off the motor.
Dayton Mod.#4K090D
115/230 v
19/9.5 amp
19/9.5 SFA
56hz
MTR Ref R607800D C303B
To vary the speed on MOST AC motors you need to vary the frequency, To do that, you need a logic speed controller, A Bit costly..
I've never tried this, But I have a Variac, Which will vary the voltage between 0 and 250 volts, It might work as a speed controller but I doubt it..probably would get to a point and just drop out altogether.
The easiest way to do that, is get a set of old Drill press pulleys and mount one on the fan shaft and one on the motor shaft, Hinge the motor on a plate and use a piece of bulky allthread to adjust it against the frame for different pulley diameters..Would only take a second to slip the belt, and readjust the tension for different speeds, and cost a lot less..
Doc is right, the only way to have a usable variable speed is with a variable frequency drive. You can do it with mechanicals (pulley size), but that is not very flexible. I also have a Variac and I tried to run a motor from it. It worked for a short time until the Variac dropped out. A variable frequency drive allows the motor to develope it's design torque at any speed. Varying the voltage will not do this and can actually harm the motor.
hmmmm i knew that variying the V would harm the motor. but never thought of varying the Freq. hmmm.
ok, i looked for VFD's and i have found 1phase input, but only 3phase output.
should i just buy a 3phase motor?
of course i would like to make what i have work, but if not??
The correct method to vary the speed of an AC motor is with a VFD. This is a Variable Frequency Drive.
The 2HP 1 phase unit is made by TECO/Westinghouse, model FM100-202-N1 and sold on the internet by Dealers Industrial Equipment, LLC. They also auction thru ebay. Looks like your under $300 for this unit.
The motor may need to be derated somewhat if you plan to operate the motor at FULL LOAD amps. If The present pulley ratio does not permit FULL load amps, you should be OK.
Spray booth wiring, motors and controls inside the booth or in the air-stream are required by the NEC (National Electric Code) to be "explosion Proof". Simply put, this means the motor, controls and wiring must be constructed and sealed so they cannot ignite an explosive gas (paint fumes) . OR- if an explosive gas becomes trapped inside a conduit and is ignited, the explosion will confined inside the conduit.
What this means is you must employ an electrician that will not compromise this Code requirement.
The VFD doesn't need to be "explosion proof" if it can be located outside the spray booth.
You may what to try a damper on the intake side of the fan to adjust the amount of air flow thru the booth.
You can operate the fan at full speed and limit the amount of air supplied to the fan. Don't limit the discharge side of the fan.
yes, a professional paint booth. all electrical is outside of booth and in conduit.
If i want 3phase i will get a singlephase to 3phase converter.
but i need to know if i even need to go that route.
that is, if i can do what i need with the equip i got already.
It's been years, Is "Explosion Proof" Nema 12 , or Nema 1 Regulations? I have forgotten..I think If I remember correctly Nema 12 was waterproof.
NEMA-4: A standard from the National Electrical Manufacturers Association, which defines enclosures intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose-directed water.
NEMA-7: A standard from the National Electrical Manufacturers Association, which defines explosion-proof enclosures for use in locations classified as Class I, Groups A, B, C or D, as specified in the National Electrical Code.
NEMA-12: A standard from the National Electrical Manufacturers Association, which defines enclosures with protection against dirt, dust, splashes by non-corrosive liquids, and salt spray.
You won't need to change the motor if you use the product that I spoke of in my previous post.
You do not need 3 phase.
The VFD will be installed in place of the existing switch you now have.
If the VFD is located outside of the booth, it will not need any special enclosure just a standard Nema 1 enclosure.
The 2HP 1 phase unit is made by TECO/Westinghouse, model FM100-202-N1 and sold on the internet by Dealers Industrial Equipment, LLC. They also auction thru ebay. Looks like your under $300 for this unit.
[vicrod
You won't be able to use your single phase motor with a VFD. A VFD's output is three phase and you'll need to swap your present motor for a three phase motor if you're going the VFD route. Three phase motors are cheap enough used- under $50 should get you a gem. So for somewhere around $350 you could make your fan variable speed.
The simpler and cheaper alternative would be as vicrod suggested- to restrict the intake of the fan. The lowbuck way would be a piece of cardboard, a slightly more expensive way would be with a set of power louvers. I believe they're available in an infinitely variable model from Grainger's. Don't worry about harming your fan motor by doing this- the restricted fan is moving less air and doing less work so the motor draws less current and heats up less- it'll last longer running at reduced load. So you'd actually be doing it (and you) a favor.
The VFD I mentioned previously is rated for 1 phase.
However, if you are going to change the motor to 3 phase it will need to be rated for the Hazardous (explosive) atmosphere in the booth and the exhaust duct. Also, get an "inverter duty" motor.
You don't want a spray booth explosion. :embarrass
vicrod
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