SA07
Electrical
- Feb 22, 2018
- 366
Hi
We had several breakdown on cooling tower pump motors since 2014. There were cables/lugs heated inside motor connection box. In 2020, since April to June, 3 motors were burnt.
We have 2 independent cooling towers for 2 turbo alternators 45 MW.
Motor nameplate :
350 kW , 742 rpm General Connection Diagram , Stator 400 / 690 V , code 9101 , Space heaters 9410 , Temp.sensor in the windings 9024 , bearings 9034 , 3 ph induction motor , mod HFG 355D , 50 Hz , , SF 1.0 , 400 / 690 V , 657,6 / 379,6 A , code G , IP 55 , Ins F , iL/iN 7 , Duty S1 , Nr : 1598190806 , AMB 40 °C , Δt 80°C , cos φ 0.8 , ALT 1000m , cooling C411 , 3190 kg , AV. PREF Waldemar ,Grubba 3000 , 89256-300-JARAGUA DOSUL SC CNPJ-07.175.725/0009-17 , Made in Brazil.
Supply voltage is 690 Vac.
We notice that the cables from the winding to the motor connection box is 95mm2. The motor nominal current is 379A. Is the cable size enough for the nominal current?
Plz see some measurements below:
14.10.14 @10.45
Motor Connection Winding temp
body box on scada
1CRF001MO 56 47 88.3
1CRF002MO 55 46 84.8
2CRF001MO 60 56 105.8
2CRF002MO 54 44 100.2
02.02.15 Current % Current A Winding Temp/DegC
Motor 1 91 345 110.1
Motor 2 91 345 105.8
Current & temperature winding
11.10.14 @11.32 13.10.14 @9.45
Current % Temp Winding Current/A Current %
1CRF001MO 89 91 337 89
1CRF002MO 89 88 337 89
2CRF001MO 91 108 343 91
2CRF002MO 91 102.7 343 91
Sometimes we have noticed water inside the motor connection box.
When we stop for annual maintenance or trip, we import power from the utility grid and run only 1 pump to save on power import. After we synchronise with the grid, we run the 2nd pump and the 2 fans. During the start-up period, there is water splashing around the cooling tower and on the motors. Can this water cause the motor to burn?
Has someone encounter similar problems with cooling tower pump motors?
Plz see attached pictures for:
Cables/lugs burnt in motor connection box
Latest motor winding damaged
We had several breakdown on cooling tower pump motors since 2014. There were cables/lugs heated inside motor connection box. In 2020, since April to June, 3 motors were burnt.
We have 2 independent cooling towers for 2 turbo alternators 45 MW.
Motor nameplate :
350 kW , 742 rpm General Connection Diagram , Stator 400 / 690 V , code 9101 , Space heaters 9410 , Temp.sensor in the windings 9024 , bearings 9034 , 3 ph induction motor , mod HFG 355D , 50 Hz , , SF 1.0 , 400 / 690 V , 657,6 / 379,6 A , code G , IP 55 , Ins F , iL/iN 7 , Duty S1 , Nr : 1598190806 , AMB 40 °C , Δt 80°C , cos φ 0.8 , ALT 1000m , cooling C411 , 3190 kg , AV. PREF Waldemar ,Grubba 3000 , 89256-300-JARAGUA DOSUL SC CNPJ-07.175.725/0009-17 , Made in Brazil.
Supply voltage is 690 Vac.
We notice that the cables from the winding to the motor connection box is 95mm2. The motor nominal current is 379A. Is the cable size enough for the nominal current?
Plz see some measurements below:
14.10.14 @10.45
Motor Connection Winding temp
body box on scada
1CRF001MO 56 47 88.3
1CRF002MO 55 46 84.8
2CRF001MO 60 56 105.8
2CRF002MO 54 44 100.2
02.02.15 Current % Current A Winding Temp/DegC
Motor 1 91 345 110.1
Motor 2 91 345 105.8
Current & temperature winding
11.10.14 @11.32 13.10.14 @9.45
Current % Temp Winding Current/A Current %
1CRF001MO 89 91 337 89
1CRF002MO 89 88 337 89
2CRF001MO 91 108 343 91
2CRF002MO 91 102.7 343 91
Sometimes we have noticed water inside the motor connection box.
When we stop for annual maintenance or trip, we import power from the utility grid and run only 1 pump to save on power import. After we synchronise with the grid, we run the 2nd pump and the 2 fans. During the start-up period, there is water splashing around the cooling tower and on the motors. Can this water cause the motor to burn?
Has someone encounter similar problems with cooling tower pump motors?
Plz see attached pictures for:
Cables/lugs burnt in motor connection box
Latest motor winding damaged
