Pump Start Contactor Problem

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Bob543

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I use a 3 hp deep pump strictly for filling a pond used for irrigation. The pond level is controlled by a Ametek 1500-G-L2-S7 liquid controller. It has always been used to stop and start a 24v sprinkler valve. Due to much maintenance I disconnected the pressure tank, pressure switch, and electric valve and now pump straight to the pond. I now use a 24/240 volt contactor. It works fine using the 24 DC transformer. The problem is when you install the Ametek controller between the transformer and the contactor, the contactor chatters, and stops and starts rapidly. Nothing is loose and all connections are tight. Could the contactor be too strong, although it works fine from the 24v trans?
 

Fitter30

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There is no such thing as a dc transformer. Since the level control is between the transformer and contactor bypass the level control see if the problem goes away. Clean the probes. After finding out what the problem is replace the contactor the contacts are burnt up. Chattering will also shorten the life of the pump.
 

Bob543

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There is no such thing as a dc transformer. Since the level control is between the transformer and contactor bypass the level control see if the problem goes away. Clean the probes. After finding out what the problem is replace the contactor the contacts are burnt up. Chattering will also shorten the life of the pump.
Thanks for the reply. Everything works fine until the 24 volt contacts are open in the level controller. When the probes are out of the water and they are closed it works normal. The same system worked fine until I replaced the 24v valve with the 24v contactor. The contactor a probes both are new. I turned the system off within seconds after realizing something was wrong.
 

Fitter30

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Thanks for the reply. Everything works fine until the 24 volt contacts are open in the level controller. When the probes are out of the water and they are closed it works normal. The same system worked fine until I replaced the 24v valve with the 24v contactor. The contactor a probes both are new. I turned the system off within seconds after realizing something
Voltages and va of transformer and brand and model of contactor? Have you measured the voltage the trans connected and contactor disconnected?
 

Bob543

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Voltages and va of transformer and brand and model of contactor? Have you measured the voltage the trans connected and contactor disconnected?
Transformer...input ac 120v 60hz 14w
output...ac 24v 300ma
Contactor...Migro drc-2x904cc
Coil 24vac
50/60 hz
Vac 240/277
Fla 40
3 hp
Transformer voltage measures 26v
Line in contactor measures 242v
Output on contactor with pump wires disconnected 242v
I took the Cutler-Hammer transformer that controls the irrigation pump and tried it and chatters too. Thank you for your replies.
 

WorthFlorida

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Thanks for the reply. Everything works fine until the 24 volt contacts are open in the level controller. When the probes are out of the water and they are closed it works normal. The same system worked fine until I replaced the 24v valve with the 24v contactor. The contactor a probes both are new. I turned the system off within seconds after realizing something was wrong.
I found the data sheet. Nicely written. Where is this 24vac coil side contractor connected to? Is it on terminals 1 & 2? Can you provide a basic siring diagram? while it is chattering, can you get a voltage reading of the 24's? The contacts for 1& 2 may be worn causing high resistance and dropping the voltage. 24v relays will usually work between 18-29 volts. A solenoid coil is more forgiving. As a test, during the chatter, short the terminals on the level controller to bypass the contacts.

I've seen 24c ac contractors chatter but generally they are well worn, perhaps lightning damage that would cause the contacts to vibrate.

 
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Fitter30

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300 ma = .3 amp Thats your problem contactor has 30 va in rush 1.25 amps . Transformer 40va 120vac to 24 vac is what you need.
Va is 40 ÷ 24 = 1.6 amps
In rush amps what it takes to pull the coil in , not to hold it in
 
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Bob543

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I found the data sheet. Nicely written. Where is this 24vac coil side contractor connected to? Is it on terminals 1 & 2? Can you provide a basic siring diagram? while it is chattering, can you get a voltage reading of the 24's? The contacts for 1& 2 may be worn causing high resistance and dropping the voltage. 24v relays will usually work between 18-29 volts. A solenoid coil is more forgiving. As a test, during the chatter, short the terminals on the level controller to bypass the contacts.

I've seen 24c ac contractors chatter but generally they are well worn, perhaps lightning damage that would cause the contacts to vibrate.


I found the data sheet. Nicely written. Where is this 24vac coil side contractor connected to? Is it on terminals 1 & 2? Can you provide a basic siring diagram? while it is chattering, can you get a voltage reading of the 24's? The contacts for 1& 2 may be worn causing high resistance and dropping the voltage. 24v relays will usually work between 18-29 volts. A solenoid coil is more forgiving. As a test, during the chatter, short the terminals on the level controller to bypass the contacts.

I've seen 24c ac contractors chatter but generally they are well worn, perhaps lightning damage that would cause the contacts to vibrate.

Thank you for the reply. Nothing is wired to 1-2. 3-4 is connected to the switch on the pump control box. 5 has one wire from the transformer and 6 going to one side of the contactor. 8-9-10 goes to the pond. 7 has a jumper to 9.
 

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Bob543

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300 ma = .3 amp Thats your problem contactor has 30 va in rush 1.25 amps . Transformer 40va 120vac to 24 vac is what you need.
Va is 40 ÷ 24 = 1.6 amps
In rush amps what it takes to pull the coil in , not to hold it in
Thank you. I will be back Monday and get that installed.
 

Waterone

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I had something similar once, turned out it was ripples in the pond making the probes turn on and off rapidly, put in a timer so once the pump started it would run for an hour then shut off.
 
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