IS 145 deg F too high for running temp on a pump motor??

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rt66electric

Senior Member
Location
Oklahoma
Newly installed propane pump/motor
explosion proof motor
operation temp at center of motor mass running at 145 deg F(FLIR camera)
ambiant temp 95 deg F
temp at bearings approx 100 deg F
pump running cool

line running amps .. 8 amps 2hp motor.

is this too high??
what is max temp before internal overtemp kicks in???

other notes
distance from 15 amp shunt trip breaker is approx 300ft using #8 wire with no splices from breaker to on/off switch, then 20 ft to motor.
another concern is 230volt motor on a 208 circuit.

another concern, a quick turn on/turn off will trip the breaker.

I have rewired entire branch circuit. Previous electrician ran #12 THHN , the old pump lasted approx 1 Year
Any thoughts or suggestion???

Thank You
Dennis
 
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retirede

Senior Member
Location
Illinois
You can’t necessarily tell if a motor is too hot by the external temperature. A standard motor with class B insulation is rated for 80C rise over 40C ambient. That’s an allowable insulation temperature of 120C which is way more than 145F.

What is the nameplate amps? What is the actual voltage at the motor?
 
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rt66electric

Senior Member
Location
Oklahoma
nameplate details

nameplate details

Nameplate details
baldor
1.5 hp T code T2C
115/230 VAC
16 / 8 amps
1725 rpm
ser F 1.00
40C amb-cont
usable 208v
 
D

drktmplr12

Senior Member
Location
South Florida
Occupation
Electrical Engineer
retirede said:
You can’t necessarily tell if a motor is too hot by the external temperature.
Click to expand...

Second this. There are too many variables to determine by touching or by IR. The only thing an operator can really do is know how hot it SHOULD feel. If it is much hotter, something may be amiss.

The thermostat in the motor, if provided, is selected to protect the insulation from excessive heat. it will trip when it needs to. If you have concerns, your best bet is to consult with the manufacturer. Get on the horn with one of their mechanical engineers and see if they would be gracious enough to help understand.
 
just the cowboy

just the cowboy

Inactive, Email Never Verified
Location
newburgh,ny
Sounds ok to me.

Sounds ok to me.

I don't see a problem at that range. I was taught if you spit on it and it don't spit back it's OK. If it was in a liquid area explosion proof setting I would worry about flash point if something was spilled. We oversize our alcohol pumps for this reason.

Cowboy
 
kwired

kwired

Electron manager
Location
NE Nebraska
just the cowboy said:
I don't see a problem at that range. I was taught if you spit on it and it don't spit back it's OK. If it was in a liquid area explosion proof setting I would worry about flash point if something was spilled. We oversize our alcohol pumps for this reason.

Cowboy
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OP says this is a propane pump motor, so one must take into consideration if it is too high temp for the hazardous location, not sure what that needs to be for propane.

Otherwise 145 F is not too hot for most motors to be able to handle.
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
That is a Baldor Ex Proof Motor for a Class 1 environment, the “Code T2C” is the maximum surface temperature and for that motor it is 230C (446F). You are nowhere even close to a problem.

There will be a red circle with a number on it between 1 and 5 which is a code for the group designation. But all 5 codes cover Group D which is propane, so it’s irrelevant.
 
Besoeker

Besoeker

Senior Member
Location
UK
Jraef said:
That is a Baldor Ex Proof Motor for a Class 1 environment, the “Code T2C” is the maximum surface temperature and for that motor it is 230C (446F). You are nowhere even close to a problem.
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Not thermal, I agree. But, if the first motor failed after a year, that indicates that there was a problem. So, I can understand why the OP would want to investigate to try to ensure that the new motor didn't suffer the same fate.

Not enough information to go on to offer constructive suggestions on what it might have been rather than what it isn't.
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Besoeker said:
Not thermal, I agree. But, if the first motor failed after a year, that indicates that there was a problem. So, I can understand why the OP would want to investigate to try to ensure that the new motor didn't suffer the same fate.

Not enough information to go on to offer constructive suggestions on what it might have been rather than what it isn't.
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retirede said:
Based on the info in your original post, plus this, I don’t see anything to be concerned about.

Do you have a failure analysis of the previous motor?
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Agreed. This doesn't appear to be a THERMAL problem, which is what you asked. One year life span is definitely cause for concern, but unless you know the failure mode of the previous motor, you can't make a reasonable assessment of what went wrong, leaving you with a long slow process of elimination. Eliminate this one.

One thing that's easy to look into though and is a frequent killer of motors is a higher than expected duty cycle. Often times on some retail operations where I have had my propane tanks filled, I have seen the operators cycle the pump motor on and off and on and off multiple times in rapid succession, because they are deciding if the tank is filled enough by shaking it and listening to the liquid slosh inside, but they can't hear it with the motor running. This last labor day weekend I took my tanks to get them filled for the BBQ and there was a long line of people getting propane. I watched the guy at the rental yard start and stop that pump probably 40-50 times in the half hour I was there. That will kill a motor in short order.
 
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rt66electric

Senior Member
Location
Oklahoma
previous pump failure probably due to voltage drop?

previous pump failure probably due to voltage drop?

previous pump failure probably due to voltage drop?

distance 300+ ft on #12 wire.


I have rewired using#8 awg without any splices.

The 15amp shunt trip breaker may trip on a quick restart.

A little miscommunication between operator and mgmt created a overtemp concern.:slaphead:

After grilling the operator.. it HAS NOT tripped on thermal overload.
 
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rt66electric

Senior Member
Location
Oklahoma
Jraef said:
Agreed. This doesn't appear to be a THERMAL problem, which is what you asked. One year life span is definitely cause for concern, but unless you know the failure mode of the previous motor, you can't make a reasonable assessment of what went wrong, leaving you with a long slow process of elimination. Eliminate this one.

One thing that's easy to look into though and is a frequent killer of motors is a higher than expected duty cycle. Often times on some retail operations where I have had my propane tanks filled, I have seen the operators cycle the pump motor on and off and on and off multiple times in rapid succession, because they are deciding if the tank is filled enough by shaking it and listening to the liquid slosh inside, but they can't hear it with the motor running. This last labor day weekend I took my tanks to get them filled for the BBQ and there was a long line of people getting propane. I watched the guy at the rental yard start and stop that pump probably 40-50 times in the half hour I was there. That will kill a motor in short order.
Click to expand...

The old motor is available... How would a person determine cause of failure??? what would be glaring evidence of undervoltage system failure? vs overload of mechanical pump lockup??


Operator (as instructed by MGMT) leaves pump running while changing cylinders.

Operator may fill 30 tanks or more, run time 1-3 hrs . The pumps system has a bypass that returns gas/liquid to main tank when it is not filling small tanks eliminating frequent start/stop.
 
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rt66electric

Senior Member
Location
Oklahoma
pump supplier is recommending a buck/boost Xfmr

pump supplier is recommending a buck/boost Xfmr

I agree with your comments that the pump is "hot", but not "too hot".
Mgmt has agreed with supplier to install a buck/boost transformer for that circuit.
Do ya'all think "it wouldn't hurt to install a buck/boost Xfmer.
Parts arrive next week.

Mean-while operator is monitoring motor temp, while filling for 30 mins.... then....resting for an hour... repeat..

Thank Ya'll for yer comments

Dennis
 
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retirede

Senior Member
Location
Illinois
IS 145 deg F too high for running temp on a pump motor??

rt66electric said:
I agree with your comments that the pump is "hot", but not "too hot".
Mgmt has agreed with supplier to install a buck/boost transformer for that circuit.
Do ya'all think "it wouldn't hurt to install a buck/boost Xfmer.
Parts arrive next week.

Mean-while operator is monitoring motor temp, while filling for 30 mins.... then....resting for an hour... repeat..

Thank Ya'll for yer comments

Dennis
Click to expand...

Given what you’ve told us so far, I would not hesitate to run continuously.

There is a good chance that the original problem was low voltage due to the length of the run. You have now fixed that by increasing the wire size - probably - did you measure voltage at the motor?

If the original motor failed due to insulation breakdown, it would fit that theory (low voltage, high current, overheating). A good motor shop can do a post-Morten.
 
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sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
Take a voltage reading at the starter with the the pump running, you uped the wire size adding a b/b could put you over voltage.
 
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