208V compressor

[checkthisout]

Shopping for compressors. I was told by the electrician we have 208v service.

Compressors with 208v motors aren't readily available.

Are 120/208 the only voltages available with this type of service?

We have 240v welders and a hoist I want to bring over from the other shop. What are options for running 240v stuff and compressor?

 

[slow]

you can use a buck boost transformer to make 208 to 240 volts.

Do you have 3 phase? if so, you have lots more options. Many hoists will run 208-240 volts. Mine at work runs off 208 without issue.

 

[checkthisout]

In poking around I did find more compressors so that should be easy enough. They are listed at 200-208V

Yes, those transformers are a bit spendy though.

Yes it's 3 phase 208

 

[checkthisout]

you can use a buck boost transformer to make 208 to 240 volts.

Do you have 3 phase? if so, you have lots more options. Many hoists will run 208-240 volts. Mine at work runs off 208 without issue.

The rating on the hoist that's already here is 208-230V (3-phase).

The rating on the hoist I want to bring over is 230-240V single phase. Are you saying these work ok on 208 single phase?

 

[Stuart in MN]

Is this in an industrial building? I assume you mean you have 208vac three phase power available, but you should confirm that.


There are many air compressors that are rated to operate on 208vac single phase or 208vac three phase (depending on the size), what brand or model are you looking at?


As for the hoist, you need to look at the nameplate information on it. Some are rated for 208-230vac operation, some are not.

 

[wyliesdiesels]

Shopping for compressors. I was told by the electrician we have 208v service.

Compressors with 208v motors aren't readily available.

Are 120/208 the only voltages available with this type of service?

We have 240v welders and a hoist I want to bring over from the other shop. What are options for running 240v stuff and compressor?

If you absolutely must have 240v, then get a 208v to 240v transformer and set a subpanel with it.

The rating on the hoist that's already here is 208-230V (3-phase).

The rating on the hoist I want to bring over is 230-240V single phase. Are you saying these work ok on 208 single phase?

no. If the motor is NOT rated for 208v(200v) then it wont work on 208v. You could cause the overloads to trip due to too much current use.

 

[checkthisout]

If you absolutely must have 240v, then get a 208v to 240v transformer and set a subpanel with it.



No. If the motor is NOT rated for 208v(200v) then it wont work on 208v. You could cause the overloads to trip due to too much current use.

After some figer'n. We're gonna get a new pump for the hoist and then just permanently station an engine driven welder we had elsewhere at the shop in lieu of getting involved with a bunch of BS with transformers.

Actual commercial electric service is a whole different ball game, that's for sure.

 

[walta]

If you are lucky your motors name plate will read like this photo 208-230 V.

If you have a very old motor that is rated for 220 volts you can operate it + or – 5% so if you local voltage measures a little on the high side as most do it will work.

If you have a very new motor that is rated for 240 volts only you can operate it + or – 5% so if you local voltage measures a little on the low side as some do it is unlikely to end well for your motor.

If it is just a few motors you could put a “small” boost transformer on each one. Google “buck boost transformer”.


Walta

 

[wyliesdiesels]

If you are lucky your motors name plate will read like this photo 208-230 V.

If you have a very old motor that is rated for 220 volts you can operate it + or – 5% so if you local voltage measures a little on the high side as most do it will work.

If you have a very new motor that is rated for 240 volts only you can operate it + or – 5% so if you local voltage measures a little on the low side as some do it is unlikely to end well for your motor.

If it is just a few motors you could put a “small” boost transformer on each one. Google “buck boost transformer”.


Walta

hopefully the overloads, if properly set, would trip, saving the motor.

 

[walta]

hopefully the overloads, if properly set, would trip, saving the motor.

The overload will hopefully stop the motor from starting a fire! The insulation in the motor is damaged every time gets hot enough to trip the overload! The insulation in the coils cannot take that much heat sooner or later it will fail and at that point the motor is almost certainly unreparable.

If the overload on a motor trips more than once there is a problem that needs to be fixed.

5% is safe.

10% is maybe OK.

15% may work for a fan with a light load or something like a lift where it runs for 30 seconds and is likely to be off for ½ hour.

I do not think anyone would not recommend operating a heavily loaded motor like a compressor at 20% under its rated voltage!


Walta

 

[Norcal]

IR did not offer a tri-volt motor for their compressors only 230/460V or single voltage 200V, a 200/230V or 208/230V is a 220V motor it can handle either a 208V or 240V supply voltage but for a hard load like a compressor and a 208V supply I agree with IR to use a 200/208V single voltage motor.

 

[checkthisout]

IR did not offer a tri-volt motor for their compressors only 230/460V or single voltage 200V, a 200/230V or 208/230V is a 220V motor it can handle either a 208V or 240V supply voltage but for a hard load like a compressor and a 208V supply I agree with IR to use a 200/208V single voltage motor.

I chose this Compressor:

"Ingersoll Rand Type 30 7.5-HP 80-Gallon Two-Stage Air Compressor (208V 3-Phase) Fully Packaged"

View media item 95039

 

[American Locomotive]

So you have 3-phase service? Most high-end welders are rated for 208-240 or have internal taps that can be setup to run on 208v. 208 is an extremely common industrial voltage.

 

[checkthisout]

So you have 3-phase service? Most high-end welders are rated for 208-240 or have internal taps that can be setup to run on 208v. 208 is an extremely common industrial voltage.

Still doing checking.......on stuff.

 

[checkthisout]

For no other reason than curiosity,

What dictates what service a building gets? That's probably not the most intelligent question as it's going to vary based on needs.

Is higher voltage better for electrical motors?

I would guess 208 service is common where most of the circuits are going to be 120V and there aren't many a/c units or industrial motors to run?

 

[Stuart in MN]

Assuming the electric utility has three phase power available in the area, they typically will provide you with either a 120/208vac or 277/480vac service (there are other voltages available, these are the most common.) If you have a facility without large motors, 120/208vac probably makes the most sense. With large motors, 277/480vac is generally better (the higher the voltage, the lower the current draw, so you can use smaller wire). However, then inside your building you'll also need your own transformer to step down to 120/208 and a second panelboard for running lights, outlets, etc.

 

[wyliesdiesels]

For no other reason than curiosity,

What dictates what service a building gets? That's probably not the most intelligent question as it's going to vary based on needs.

Is higher voltage better for electrical motors?

I would guess 208 service is common where most of the circuits are going to be 120V and there aren't many a/c units or industrial motors to run?

Thats very dependent on PoCo and building use permit/plans.

Around here, its either 208Y/120 or 480Y/277. 208Y for office/small warehouse type buildings and 480Y for large buildings such as schools, plants, etc

The local PoCo does not offer 240D/120 for new service though theres quite a few existing buildings that still have it.

 

[fitter30]

Most motors are not a single voltage that would limit what there motors would work on. A 230 volt motor has +or - 10% = 207volts but starting torque will be decrease by 20-25%. Larger air compressors once started for the day don't shut off just cycle on a unloader.

 

[Norcal]

Most motors are not a single voltage that would limit what there motors would work on. A 230 volt motor has +or - 10% = 207volts but starting torque will be decrease by 20-25%. Larger air compressors once started for the day don't shut off just cycle on a unloader.

Running a motor at the bottom end of the allowable range is poor practice and that is going to be asking for trouble if there is a drop in the supply voltage.

 

[Milton Shaw]

One quick check is to check the pole coming into the building and the number of transformers on it. If one transformer single phase, if three transformers you have three phase. Three phase motors are a lot stronger start than any single phase motor that has to depend on start switches/windings/capacitors to get the starting turn. That is why most business are three phase as the motors are simpler and can be reversed just by switching any two of the three wires.

 

[wyliesdiesels]

One quick check is to check the pole coming into the building and the number of transformers on it. If one transformer single phase, if three transformers you have three phase. Three phase motors are a lot stronger start than any single phase motor that has to depend on start switches/windings/capacitors to get the starting turn. That is why most business are three phase as the motors are simpler and can be reversed just by switching any two of the three wires.

This is not accurate as there are single housing transformers that have 3 primary bushings and 4 secondary lugs for wye service- 208Y/120 or 480Y/120. I often see them out in ag fields where there is a well pump...

In regards to your comment about start switches(do you mean motor starters?) and windings, many large motors require dual motor starters to do a part winding start because the PoCo service does not have enough power to handle an "across the line start" which on a large motor can be hundreds or thousands of amps for split seconds.

couple years back i was working on a 100a motor for a turbine pump well. We had to use dual motor starters to do a partial winding start setup as the PoCo feed was small, out in the country, and could not handle an across the line start from the motor.

 

[checkthisout]

I'm an idiot.

The hoist we want to move has the motor labeled 208-230V, currently running on 240 so all is well.

 

[Norcal]

I'm an idiot.

The hoist we want to move has the motor labeled 208-230V, currently running on 240 so all is well.

Your not the first person to either fail to read the label, or misread it.