480V vs 460V

[Drod04Mustang]

So recently a 460V Air compressor was said to be blown(electrical motor).

Here is the info on the motor-
Product line : W40 NEMA Premium Efficiency ThreePhase Product code : 14367176 Catalog # : 04036OT3E286TS-W40 Frame Output Poles Frequency Rated voltage Rated current L. R. Amperes LRC No load current Rated speed Slip Rated torque Locked rotor torque Breakdown torque Insulation class Service factor Moment of inertia (J) Design : 284/6TS : 40 HP (30 kW) : 2 : 60 Hz : 230/460 V : 93.7/46.8 A : 609/304 A : 6.5x(Code G) : 30.8/15.4 A : 3540 rpm : 1.67 % : 59.3 ft.lb : 190 % : 240 % : F : 1.25 : 2.02 sq.ft.lb : B Locked rotor time Temperature rise Duty cycle Ambient temperature Altitude Protection degree Cooling method Mounting Rotation¹ Noise level² Starting method Approx. weight³ : 14s (cold) 8s (hot) : 80 K : Cont.(S1) : -20°C to +40°C : 1000 m.a.s.l. : IP23 : IC01 - ODP : F-1 : Both (CW and CCW) : 73.0 dB(A) : Direct On Line : 339 lb Output 25% 50% 75% 100% Foundation loads Efficiency (%) 91.5 91.7 92.4 92.4 Max. traction Power Factor 0.51 0.76 0.84 0.87 Max. compression Drive end Non drive end Bearing type : 6311 Z C3 6211 Z C3 Sealing : Without Bearing Seal Without Bearing Seal Lubrication interval : 20000 h 20000 h Lubricant amount : 18 g 11 g Lubricant type : Mobil Polyrex EM Notes USABLE @208V 104A SF 1.15 SFA 119A This revision replaces and cancel the previous one, which must be eliminated. (1) Looking the motor from the shaft end. (2) Measured at 1m and with tolerance of +3dB(A). (3) Approximate weight subject to changes after manufacturing process. (4) At 100% of full load. These are average values based on tests with sinusoida

The tech said that there was too much power going to the disconnect to the top of the motor starter. I read the amperage and it read appr- 491V, 495V, 496V leg to leg. each leg to neutral was around 270V. The system says 460. the voltage seems correct but trying to get a second opinion

 

[infinity]

The tech said that there was too much power going to the disconnect to the top of the motor starter. I read the amperage and it read appr- 491V, 495V, 496V leg to leg. each leg to neutral was around 270V. The system says 460. the voltage seems correct but trying to get a second opinion

I think that you meant voltage not amperage. Your numbers (phase to neutral) do not seem correct for a properly installed Wye system.

 

[zbang]

460 is the utilization voltage of the motor, 480 is the nominal system voltage (495v is only a few percent high); no problem there. OTOH, phase-to-neutral should be about 286 volts if the phase-phase is 495.

Here's a pinned post about system/nominal and utilization voltage, it's worth reading.

Voltage Ratings: 110/115/120, 220/230/240 or 440/460/480

This subject comes up a LOT in this and other forums, so I thought it would be a good idea to make it a "Sticky" that can be found and referred to easily when it comes up. There are two "standards" for voltage in North America depending on which END of the wire you are looking at; "Distribution...

forums.mikeholt.com

 

[retirede]

Have you verified that the motor has, indeed, failed? If so, a bit of forensic analysis is in order.

 

[Krusscher]

Have you verified that the motor has, indeed, failed? If so, a bit of forensic analysis is in order.

How old is this motor? maybe it is short cycling? has it tripped over loads recently?

 

[Drod04Mustang]

Well I ohmed out and it seemed ok. They took the motor to rewind it. Cant check it out anymore. The motor is about 3 years old and only used like 1.5 years because the plant was down. has it tripped over loads recently?-Yes welded a heater together. But still would work. I will updated everyone when we get it back. Thanks.

 

[retirede]

Well I ohmed out and it seemed ok. They took the motor to rewind it. Cant check it out anymore. The motor is about 3 years old and only used like 1.5 years because the plant was down. has it tripped over loads recently?-Yes welded a heater together. But still would work. I will updated everyone when we get it back. Thanks.

“welded a heater together?”….what does that mean?

 

[Drod04Mustang]

“welded a heater together?”….what does that mean?

The heater on this motor starter pictured below. Originally they changed the motor starter out. Ran about a month and a half and blew a fuse on a seperate radiator fan connected to the air compressor contol. Finally took the motor starter apart and notice that 1 of the heaters had welded together. So when the motor was initialized it ran and did not have a OC protection in case it got to hot. So i stopped messing with it because i could not find a replacment for it. The Air Comprssor guys came out and check it out. and said the motor was bad. I ohmed out the motor and it seems to be fine. Sorry this is so vage but Im new to motor starters.

 

[retirede]

The elements in the series with the motor conductors (what I think you’re calling “heaters”) are not contacts, so I still don’t understand what you mean by welded together.

Will the compressor run so you can take some current readings?

 

[Drod04Mustang]

Actual product may vary from displayed image(s)

Eaton H2005B-3 1.20 - 1.96 Amp Fast Trip Heater Pack for Freedom and Definite Purpose (Set of 3)​

SKU / MPN:
H2005B-3

 

[Drod04Mustang]

Ok Good Morning,


Have a problem. I got the motor rewound and new and the first time they turn it on it tripped the main breaker.

100 Amp Square D 480V 3 phase breaker

The readings are as follows.

496 Leg to leg
497 leg to leg
495 outside leg to outside leg

237.5 leg to neurtral
236 leg to neutral
237.3 leg to neutral

0.04 Ground to neutral

Gonna try to change out breaker first.

 

[kwired]

Ok Good Morning,


Have a problem. I got the motor rewound and new and the first time they turn it on it tripped the main breaker.

100 Amp Square D 480V 3 phase breaker

The readings are as follows.

496 Leg to leg
497 leg to leg
495 outside leg to outside leg

237.5 leg to neurtral
236 leg to neutral
237.3 leg to neutral

0.04 Ground to neutral

Gonna try to change out breaker first.

If this is a 480/277 volt supply the line to neutral voltage is not right. If you have ~496 volts line to line you should have about 286 to neutral.

If this is a delta supply it will depend on where it is grounded or if it is grounded. But with voltages to neutral you are getting I am suspecting it is not grounded, whether intentionally or not.

 

[Drod04Mustang]

Ok Good Morning,


Have a problem. I got the motor rewound and new and the first time they turn it on it tripped the main breaker.

100 Amp Square D 480V 3 phase breaker

The readings are as follows.

496 Leg to leg
497 leg to leg
495 outside leg to outside leg

237.5 leg to neurtral
236 leg to neutral
237.3 leg to neutral

0.04 Ground to neutral

Gonna try to change out breaker first.

 

[Drod04Mustang]

If this is a 480/277 volt supply the line to neutral voltage is not right. If you have ~496 volts line to line you should have about 286 to neutral.

If this is a delta supply it will depend on where it is grounded or if it is grounded. But with voltages to neutral you are getting I am suspecting it is not grounded, whether intentionally or not.

Sorry-fingers wrote that wrong.


287.5 leg to neurtral
286 leg to neutral
287.3 leg to neutral

 

[kwired]

Did they try again or have not ran it since?

Is there magnetic trip adjustment on the breaker? May not be too common on a 100 amp breaker but over 125 it can be more common. Factory setting is usually the lowest setting. Some cases a motor will need to have that turned up to allow starting.

 

[Krusscher]

Make sure the motor is tapped for the high voltage

 

[ptonsparky]

Actual product may vary from displayed image(s)

Eaton H2005B-3 1.20 - 1.96 Amp Fast Trip Heater Pack for Freedom and Definite Purpose (Set of 3)​

SKU / MPN:
H2005B-3

That is the heater. It should read continuity with a simple tester, but show some resistance with a proper meter.

 

[kwired]

That is the heater. It should read continuity with a simple tester, but show some resistance with a proper meter.

Not sure what he meant when he said welded if this is what he was talking about. They usually are ok or if they have been severely overloaded they melt to an open state.

 

[ptonsparky]

... they melt to an open state.

I did that once. More like blew the solder out of them. (Insert embarrassed as heck emoji).

 

[LarryFine]

(Insert embarrassed as heck emoji).