Ingersoll rand t30 80 gallon

[BenFabWeld]

So I have a Ingersoll Rand t30 that was built in 2000. The guy I bought it off of said the 7.5hp electric motor stopped working and when it did, it made a humming noise, kinda like it seized up, but it still rotates. Anyways he took the power wire off and doesn't know how it was hooked up, weird I know. But it's a 1 phase, 40 amp motor, with an external power box, not wired to the on/off switch. I'll attach pics. I need help with the wiring. I'd hate have the motor looked at and pay for diagnostic when he may have had it wired wrong. And I'd hate to smoke the motor again if it did get a rebuild.

 

[The Cobbler]

where are the wires for the pressure switch ? Is that the wires he took off? are there any loose wires ?
with a hum and won;t start on it's own I would suspect the start capacitor

 

[The Cobbler]

moved to electrical section .

 

[BenFabWeld]

Wires from that black box go to the pressure switch. He took the supply power cable to the black box. I can't diagnose the motor until I have a supply power cable.

 

[TurnipTruck]

The *********/white/green cord going through the top of the enclosure should go to the motor.
The smaller cord out the side should go to the pressure switch.
The hole in the bottom is where the power used to come in, and the two hot leads (whatever color they are) will be landed at the two large terminals at the top, plus a green ground to the ground screw on the back wall.
240v!

 

[BenFabWeld]

The *********/white/green cord going through the top of the enclosure should go to the motor.
The smaller cord out the side should go to the pressure switch.
The hole in the bottom is where the power used to come in, and the two hot leads (whatever color they are) will be landed at the two large terminals at the top, plus a green ground to the ground screw on the back wall.
240v!

That's what I was thinking honestly. I just wanted to be sure. So I'll just wire up a 4 prong outlet and wire the compressor the same and just double up the ground and neutral

 

[TurnipTruck]

It doesn’t need a neutral.

 

[BenFabWeld]

It doesn’t need a neutral.

Correct. But the range stove I'll be using right next to it will.

 

[The Cobbler]

double up the ground and neutral

the range stove I'll be using right next to it will.

no to doubling up the ground & neutral, just don't use the neutral.
and, that plug/outlet is not rated for a 5hp motor load.

 

[Norcal]

no to doubling up the ground & neutral, just don't use the neutral.
and, that plug/outlet is not rated for a 5hp motor load.

Correct, but the OP stated it was a 7.5 HP motor, it is hack work to cord & plug connect 5 HP & larger motors unless one is prepared to spend some serious dough for a properly rated device, just cheaper to use a disconnect switch & hard wire it.

 

[The Cobbler]

OP stated it was a 7.5 HP motor

oop's . I guess I better learn how to read

 

[Norcal]

oop's . I guess I better learn how to read

I wish folks in the ER & doctors offices would learn to read, they keep calling me Ronald & that is not my name.

 

[mm08822]

If you are replacing the feed with rubber cord then it will have to be 6-3. Has to be 125% of 40amps. #8 is only rated for 40a and #6 is good for 55 amps.

If you use thhn/thwn, then #8 copper is fine b/c it's rated for 55amps.

 

[mm08822]

I wish folks in the ER & doctors offices would learn to read, they keep calling me Ronald & that is not my name.

Possible similarities causing confusion?

 

[BenFabWeld]

They sell 6 foot, 6 gauge, 4 prong 50 amp pre made power cables at home depot, I'll buy that. And I'll also buy a dual pole 40/40 amp breaker. The plate on the side of the motor says the it's only 32 amp draw

 

[mm08822]

The 2pole 40A cb most likely will be too small for for startup current. A 50 or 60a will most likely be needed.

As Ronald Norcal stated, it needs to be hardwired.

 

[wyliesdiesels]

That's what I was thinking honestly. I just wanted to be sure. So I'll just wire up a 4 prong outlet and wire the compressor the same and just double up the ground and neutral

a nema 14-50 is NOT rated for 7.5hp. This motor should be hardwired.

you will need 50a rated wire for the circuit (40a FLC x 1.25a = 50a). So either #8 THHN in conduit or 6/2 NM-b

 

[wyliesdiesels]

Correct. But the range stove I'll be using right next to it will.

so run 2 separate circuits then.

 

[wyliesdiesels]

They sell 6 foot, 6 gauge, 4 prong 50 amp pre made power cables at home depot, I'll buy that. And I'll also buy a dual pole 40/40 amp breaker. The plate on the side of the motor says the it's only 32 amp draw

dont buy that. make your own whip with FMC and stranded THHN.

Also, if the compressor is more than 50' away from and not within sight of the breaker panel, you will need a local disconnect.

a 40a breaker will most likely nuisance trip due to the in-rush current of the motor. a 50a or 60a may be required. you can go up to 100a breaker

 

[BenFabWeld]

Is anyone able to see the pictures im posting? This will suffice. 6 gauge 4 wire rated for 50 amps. I'm going to wire a 50 amp receptacle a foot from the panel in the shop. And I'll be able to swap between the compressor and the range stove for powder coated parts. It'll be fine, and guess what. If it isn't the breaker will trip, that's what it's meant to do. Appreciate all your help guys. I got it from here.

 

[wyliesdiesels]

yes we can see the pic.

DONT USE THAT for the compressor. its not code compliant and its hack work!

If you need a 50a circuit for an oven, install a separate hardwired circuit for the compressor.

 

[TurnipTruck]

My brother has a snapon 7.5hp compressor and he gets about two years out of his 50a plug&receptacle before it melts. I have repeatedly told him he needs to hardwire it, but he knows better.

 

[Leaflessshadetree]

Is there some reason for not running a second circuit? Especially since it is that close. If further away I'd recommend a sub panel and separate circuits from there.

 

[BenFabWeld]

Is there some reason for not running a second circuit? Especially since it is that close. If further away I'd recommend a sub panel and separate circuits from there.

Ease of just using one (not at the same time) circuit not 2. The range and compressor wont be used at the same time, ever. And the compressor isnt going to be used non stop.

The sub panel is in the garage. The run from the house to garage(shop) panel is about 75ish feet. At least they did the run in the correct wire size.

If it comes down to it, I can just get a less hp motor that draws less power that spins the same rmp needed to run the pump. Which is 3450 rpm, which are available for relatively cheap.

The more I look in the black box on the compressor, the more I wonder how this guy had this wired. Only 1 lug has been touched to hook this up. I can tell by the screw driver marks. One of the lugs is brand new, hasn't been touched. So bizarre.

Anyways, I understand what you guys are saying about the receptacle, and just hard wire it. That would mean I would need 2 more additional 50 amp dual pole breakers and I don't have enough room in the panel for that, with the other circuits in the panel. That would mean I'd have 3-50 amp cb's in the panel along with everything else. As it is, I have to swap over the plasma cutter and welder when I need the other one. At most id be running compressor and plasma at the same time. Not compressor and range, or compressor and welder.

 

[ericm]

Anyways, I understand what you guys are saying about the receptacle, and just hard wire it. That would mean I would need 2 more additional 50 amp dual pole breakers and I don't have enough room in the panel for that, with the other circuits in the panel. That would mean I'd have 3-50 amp cb's in the panel along with everything else. As it is, I have to swap over the plasma cutter and welder when I need the other one. At most id be running compressor and plasma at the same time. Not compressor and range, or compressor and welder.

Sounds like you need a new panel.

 

[Norcal]

Sounds like you need a new panel.

Or the cheap solution & use a quad breaker to make room.

 

[wyliesdiesels]

Not sure what the point of coming on here for advice is if you dont want to follow it.

you have numerous electricians telling you to hardwire the motor and you come up with all kinds of excuses of why you cant

if your panel is out of room, swap it for a bigger one or install another subpanel

your other option is to get a double pole double double throw switch connect it to a 50a breaker, then connect a 50a receptacle and a hardwired junction box to it for the compressor.

 

[walta]

Does the motor pass the sniff test? It seems likely that the motor windings were burned when the motor stalled. Put your nose by the motor’s vents and give it a good sniff. If it smells burnt the motor is almost certainly damaged beyond repair.

 

[Balvar24]

7.5 HP is a lot of inrush for a single phase circuit.

Start-capacitor?

 

[Norcal]

7.5 HP is a lot of inrush for a single phase circuit.

Start-capacitor?

A 7.5 HP motor in a residential application may run afoul of the PoCo's regulations/tariffs

 

[BenFabWeld]

K, so. I am taking the advice and will hard wire it to the panel in the shop. From compressor to panel is 4ish feet. From shop panel to house panel is roughly 110-120 feet wired with 2awg aluminum straight to lugs on house panel. I am hoping this is sufficient, considering the homework I did with figuring that out.

Also with the info that is on the compressor placard, the actual compressor needs 3450 rpms to operate.

Could I get away with a smaller electirc motor, that spins the same rmp to operate the compressor?

Cause I can find motors that spin that rpm for probably cheaper than it would be to repair assuming it's busted.

 

[mm08822]

K, so. I am taking the advice and will hard wire it to the panel in the shop. From compressor to panel is 4ish feet. From shop panel to house panel is roughly 110-120 feet wired with 2awg aluminum straight to lugs on house panel. I am hoping this is sufficient, considering the homework I did with figuring that out.

Also with the info that is on the compressor placard, the actual compressor needs 3450 rpms to operate.

Could I get away with a smaller electirc motor, that spins the same rmp to operate the compressor?

Cause I can find motors that spin that rpm for probably cheaper than it would be to repair assuming it's busted.

Any motor spinning at 3450rpm will need the 7.5 HP capability (assuming the original 7.5 HP motor was not oversized).

A lower HP motor (e.g. 5HP) spinning @1750rpm would use less energy but halve the SCFM of the compressor. This might be ok for you with the 80 gallon tank, but you have to determine that based on your expected usage.
Based on the peak amps measured in this 5 HP example, there may be some room to increase the pulley diameter on the motor to increase the SCFM a little more from 50%..

 

[ericm]

It takes a fixed amount of power to run the pump at a given rpm. If you use a smaller motor you will need to change the pulleys so the pump turns slower and needs less power. You should be able to find a chart for the pump showing motor HP and pump rpm.

BTW the pump probably does not need to turn 3450 rpm, that's the motor speed. The pump speed will be about 1/3 or 1/4 of that.

 

[dave*99]

From shop panel to house panel is roughly 110-120 feet wired with 2awg aluminum straight to lugs on house panel.

Through a breaker?

 

[BenFabWeld]

Through a breaker?

Yes. The house panel has a 60 amp breaker to the shop. I didn't word that correctly

 

[BenFabWeld]

This is where I loaded what the compressor is doing when I try to turn it on. And damn does draw some power. Makes the lights in the shop and the house flicker. Any insight would help. I am guessing the guy was right and the motor is cooked?

https://www.reddit.com/r/AirCompression/s/wqQf9cWmBf

 

[BenFabWeld]

It takes a fixed amount of power to run the pump at a given rpm. If you use a smaller motor you will need to change the pulleys so the pump turns slower and needs less power. You should be able to find a chart for the pump showing motor HP and pump rpm.

BTW the pump probably does not need to turn 3450 rpm, that's the motor speed. The pump speed will be about 1/3 or 1/4 of that.

This is the label on the side. It says 1500 rpm for the pump. Would I be a able to use a 5 hp motor with the same pulley as long as the motor is spinning at the same speed as the 7.5? I don't see it would make any difference other than maybe the motor working a little harder than the 7.5? I won't be using this compressor non stop for weeks on end. I basically have a hobby shop and am only in here max 5 time a week, for a few hours each time.

 

[American Locomotive]

This is where I loaded what the compressor is doing when I try to turn it on. And damn does draw some power. Makes the lights in the shop and the house flicker. Any insight would help. I am guessing the guy was right and the motor is cooked?

https://www.reddit.com/r/AirCompression/s/wqQf9cWmBf

It sounds like it just has a bad start capacitor or start switch. It's probably an easy, cheap fix.

This is the label on the side. It says 1500 rpm for the pump. Would I be a able to use a 5 hp motor with the same pulley as long as the motor is spinning at the same speed as the 7.5? I don't see it would make any difference other than maybe the motor working a little harder than the 7.5? I won't be using this compressor non stop for weeks on end. I basically have a hobby shop and am only in here max 5 time a week, for a few hours each time.

If there were no difference, the compressor would have come with a 5HP motor, not a 7.5. A 7.5HP motor is 50% more powerful than a 5HP - that's quite a bit more "than a little harder".

 

[BenFabWeld]

It sounds like it just has a bad start capacitor or start switch. It's probably an easy, cheap fix.


If there were no difference, the compressor would have come with a 5HP motor, not a 7.5. A 7.5HP motor is 50% more powerful than a 5HP - that's quite a bit more "than a little harder".

How would I know if it was those that are bad? Besides the motor not turning?

 

[American Locomotive]

How would I know if it was those that are bad? Besides the motor not turning?

Open up the capacitor box and take a look. Sometimes they're obviously blown up. They're also pretty cheap to just try and replace if you have no means of testing them.