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    Motor housing HOT, with no load on pump???

    Need advice on motor temperatures/problems. Commissioning a machine and I noticed the motor is getting hot! It is on a water pump for recirculating water thru a heat exchanger. So no real load to speak of on it.

    Been running the motor for about 45 minutes – 1 hour and the motor is getting pretty hot, hotter than the pump in fact. I checked all the obvious things like wiring, amp draw etc. and everything is fine. It’s pulling about 5 – 5.5 amps with an FLA of 6.5 amps and SFA of 7.46. The fluid temp is only about 90 degrees and there’s been no load to speak of on the motor.

    You can see from the pictures below that the rear of the motor is significantly hotter than the front of the motor, which seems to point to a bad bearing. There are no greese fittings either.

    Any ideas???

    Click image for larger version

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    #2
    Originally posted by emiller233 View Post
    Need advice on motor temperatures/problems. Commissioning a machine and I noticed the motor is getting hot! It is on a water pump for recirculating water thru a heat exchanger. So no real load to speak of on it.

    Been running the motor for about 45 minutes – 1 hour and the motor is getting pretty hot, hotter than the pump in fact. I checked all the obvious things like wiring, amp draw etc. and everything is fine. It’s pulling about 5 – 5.5 amps with an FLA of 6.5 amps and SFA of 7.46. The fluid temp is only about 90 degrees and there’s been no load to speak of on the motor.

    You can see from the pictures below that the rear of the motor is significantly hotter than the front of the motor, which seems to point to a bad bearing. There are no greese fittings either.

    Any ideas???

    [ATTACH=CONFIG]23067[/ATTACH]
    How hot?

    Comment


      #3
      Originally posted by emiller233 View Post
      Need advice on motor temperatures/problems. Commissioning a machine and I noticed the motor is getting hot! It is on a water pump for recirculating water thru a heat exchanger. So no real load to speak of on it.

      Been running the motor for about 45 minutes – 1 hour and the motor is getting pretty hot, hotter than the pump in fact. I checked all the obvious things like wiring, amp draw etc. and everything is fine. It’s pulling about 5 – 5.5 amps with an FLA of 6.5 amps and SFA of 7.46. The fluid temp is only about 90 degrees and there’s been no load to speak of on the motor.

      You can see from the pictures below that the rear of the motor is significantly hotter than the front of the motor, which seems to point to a bad bearing. There are no greese fittings either.

      Any ideas???

      [ATTACH=CONFIG]23067[/ATTACH]
      If I am reading that right 117F is the highest temp in the image. That is not really all that hot for this kind of situatioun. Low enough temp you can touch it without getting burned, though it may eventually burn you if you leave your hand there for too long.

      Might be that back bearing is going out and is making that end hotter. Might be the pumped media is cooler so it is taking some heat with it and making that end a little cooler.

      Is it running across line or on a VFD? internal cooling fans run slower when motor runs slower and pull less cooling air over the motor.
      I live for today, I'm just a day behind.

      Comment


        #4
        Doesn’t seem all that hot to me and that looks like the motor windings creating all the heat to me. Not a rear bearing. My SEWAG.
        Tom
        TBLO

        Comment


          #5
          Originally posted by ptonsparky View Post
          Doesn’t seem all that hot to me and that looks like the motor windings creating all the heat to me. Not a rear bearing. My SEWAG.
          SEWAG?

          Comment


            #6
            Originally posted by Besoeker3 View Post
            SEWAG?
            My SEWAG to that SEWAG is Semi-Educated Wild-A$$ Guess.
            Master Electrician
            Electrical Contractor
            Richmond, VA

            Comment


              #7
              We've used these many times, just dont remember one being quite this hot before... yes 117 was the top. It did get a few degrees warmer. I think it topped out at 126.

              It's just recirculating water for a heat exchanger. I think the water was about 80 degrees. It's cool in here today.

              It's just across the line, I think it was a 1800RPM (I left already).

              Comment


                #8
                SEWAG haha. I might have to steal that!

                Comment


                  #9
                  Originally posted by LarryFine View Post
                  My SEWAG to that SEWAG is Semi-Educated Wild-A$$ Guess.
                  Thank you, LF.
                  My ignorant Brit brain is constantly being upgraded here.......

                  Comment


                    #10
                    "pretty hot" measure by palm is not scientific approach. motor can easily reach 210F, it's normal working temperature of many types of motors. https://www.plantengineering.com/art...ow-hot-is-hot/

                    Sent from my ONEPLUS A6013 using Tapatalk

                    Comment


                      #11
                      Originally posted by emiller233 View Post
                      Need advice on motor temperatures/problems. Commissioning a machine and I noticed the motor is getting hot! It is on a water pump for recirculating water thru a heat exchanger. So no real load to speak of on it.

                      Been running the motor for about 45 minutes – 1 hour and the motor is getting pretty hot, hotter than the pump in fact. I checked all the obvious things like wiring, amp draw etc. and everything is fine. It’s pulling about 5 – 5.5 amps with an FLA of 6.5 amps and SFA of 7.46. The fluid temp is only about 90 degrees and there’s been no load to speak of on the motor.

                      You can see from the pictures below that the rear of the motor is significantly hotter than the front of the motor, which seems to point to a bad bearing. There are no greese fittings either.

                      Any ideas???

                      [ATTACH=CONFIG]23067[/ATTACH]
                      117F is not hot, it is 'slightly warm'

                      95F surrounding, 22F rise only.

                      Comment


                        #12
                        Originally posted by junkhound View Post
                        117F is not hot, it is 'slightly warm'

                        95F surrounding, 22F rise only.
                        But associated with that specific region of the motor, it is still a troubling observation!

                        Comment


                          #13
                          Originally posted by GoldDigger View Post
                          But associated with that specific region of the motor, it is still a troubling observation!
                          The other end of the motor is connected to the pump, which is pulling heat out along the rotor shaft and into the impeller, then into the water as it flows through. Very common issue with IR scans of water pumps.
                          __________________________________________________ ____________________________
                          Many people are shocked when they discover I am not a good electrician...

                          I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

                          Comment


                            #14
                            Originally posted by Jraef View Post
                            The other end of the motor is connected to the pump, which is pulling heat out along the rotor shaft and into the impeller, then into the water as it flows through. Very common issue with IR scans of water pumps.
                            True, but in this case is the thermograph a valid indication of high bearing temperature rather than winding temperature? Or are we just seeing openings in the motor housing?

                            Comment


                              #15
                              I checked with the MFGR, they said 105C is max acceptable limit.
                              But, we've used this setup quite a few times before and it never was this warm before, that we can remember anyways. That's why we checked it to see what temp of it actually was.
                              Today it went up to 144F. Still cool out in the shop, around 80 again today.

                              Comment

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