l00semarble
New Member
Pump is 1.5hp Franklin single phase 3-wire. Control box diagram below.
Issue: When power sent to control box the pump pulls 41a (about 31a on red/run and 11a on yel/start) and pump does not run. After a little bit main overload breaker on control box trips.
Steps done:
- Pump windings measure correct on ohmmeter. Windings not shorted to ground and winding resistance is per Franklin specs.
- Both capacitors test in spec with Fluke multimeter capacitance test
- Relay coil (per test C) tests in spec
- Relay contacts (per test D) tests in spec (dead short)
- Voltage holds at at least 230v leg to leg and each at least 120v to ground even during 40a load so I don't think there is a voltage supply issue.
- Pump pulled and checked for locked rotor condition. Rotor can be turned by grabing shaft with channel locks. It is stiff but it does move. Not sure how stiff is normal. Pump stack can be rotated by hand.
I am most suspecting the relay but I don't understand it. I assume is normally closed and that internally pin 2 is other other end of the coil so it seems that the coil would always be energized and therefor the contacts open and start cap out of circuit. But maybe the thing has an internal delay or maybe it takes time for voltage to build on the start winding to energize pin 2? or???
I pulled off the wire from #2 on relay as I wanted to test if full voltage was coming through the contacts or actually if it was opening the contacts once energized. With #2 disconnected and the box energized the relay chatters which would be because it is normally closed so 1 energizes 2 which then fires coil which opens contact and deenergizes 2 which then closes contact and reenergize 2 and back and forth . This seems to confirm that pin 2 being energized does hold it open and does seem to kind of confirm the relay is trying to work if it is just a simple relay.
Is this relay just a simple mechanical relay (coil closes contacts) or is there somethign more complicated going on in there?
Also, for what its worth the pump has been abused. The installation is in Costa Rica and it was done "Tico" style. This is not a normal drilled well but a makeshift shallow well at the bottom of a ravine in the jungle with a stream. The pump has been subjected to silting and also is installed in a 3ft diameter well without a flow concentrator to force water to flow over pump body to cool it.
One other odd thing. As I am troubleshooting by myself it is difficult because the well/pump is a difficult 10 minute hike down into the jungle but the control box up at the top so I can't see the pump when actuating the power. When I had the pump motor disconnected from the pump body I left it laying there out of the water with the shaft free to spin in the air. I went back to control box and did more troubleshooting and found the same overload current. I only applied power to the box for a few seconds at a time to troubleshoot. Same exact symptoms with motor shaft connected to nothing. BUT....when I hiked back down to the pump which was at least 10 minutes I was surprised that the motor was HOT. Not just slightly warm but hot enough that I could only keep my hand on it for 4-5 seconds before it was uncomfortable. How the hell could it get that hot with me just energizing it for a few seconds at a time maybe 7-8 times?
Sorry for long....I'll end it here.
Issue: When power sent to control box the pump pulls 41a (about 31a on red/run and 11a on yel/start) and pump does not run. After a little bit main overload breaker on control box trips.
Steps done:
- Pump windings measure correct on ohmmeter. Windings not shorted to ground and winding resistance is per Franklin specs.
- Both capacitors test in spec with Fluke multimeter capacitance test
- Relay coil (per test C) tests in spec
- Relay contacts (per test D) tests in spec (dead short)
- Voltage holds at at least 230v leg to leg and each at least 120v to ground even during 40a load so I don't think there is a voltage supply issue.
- Pump pulled and checked for locked rotor condition. Rotor can be turned by grabing shaft with channel locks. It is stiff but it does move. Not sure how stiff is normal. Pump stack can be rotated by hand.
I am most suspecting the relay but I don't understand it. I assume is normally closed and that internally pin 2 is other other end of the coil so it seems that the coil would always be energized and therefor the contacts open and start cap out of circuit. But maybe the thing has an internal delay or maybe it takes time for voltage to build on the start winding to energize pin 2? or???
I pulled off the wire from #2 on relay as I wanted to test if full voltage was coming through the contacts or actually if it was opening the contacts once energized. With #2 disconnected and the box energized the relay chatters which would be because it is normally closed so 1 energizes 2 which then fires coil which opens contact and deenergizes 2 which then closes contact and reenergize 2 and back and forth . This seems to confirm that pin 2 being energized does hold it open and does seem to kind of confirm the relay is trying to work if it is just a simple relay.
Is this relay just a simple mechanical relay (coil closes contacts) or is there somethign more complicated going on in there?
Also, for what its worth the pump has been abused. The installation is in Costa Rica and it was done "Tico" style. This is not a normal drilled well but a makeshift shallow well at the bottom of a ravine in the jungle with a stream. The pump has been subjected to silting and also is installed in a 3ft diameter well without a flow concentrator to force water to flow over pump body to cool it.
One other odd thing. As I am troubleshooting by myself it is difficult because the well/pump is a difficult 10 minute hike down into the jungle but the control box up at the top so I can't see the pump when actuating the power. When I had the pump motor disconnected from the pump body I left it laying there out of the water with the shaft free to spin in the air. I went back to control box and did more troubleshooting and found the same overload current. I only applied power to the box for a few seconds at a time to troubleshoot. Same exact symptoms with motor shaft connected to nothing. BUT....when I hiked back down to the pump which was at least 10 minutes I was surprised that the motor was HOT. Not just slightly warm but hot enough that I could only keep my hand on it for 4-5 seconds before it was uncomfortable. How the hell could it get that hot with me just energizing it for a few seconds at a time maybe 7-8 times?
Sorry for long....I'll end it here.