replacing start stop push switch with relay

Thread Starter

Niladri Pal

Joined Jun 21, 2017
18
I want to replace the start stop switch with relay in this water pump starting panel.what will be ratings of ralay or how much current flows in this start stop switch
Details of submersible pump and control panel is given in the image
 

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#12

Joined Nov 30, 2010
18,167
The label says 1 HP and 10 amps. Relays are rated both ways. I would never install the minimum possible relay. Anything up to double the nameplate rating, like AVINASH said. Right now, the voltage is not revealed, but American 120 VAC seems likely. Your relay needs to be rated for at least 120 VAC. Most of them are rated for 240 VAC.

This is not a rare problem and the proper parts are easily available.
 
Well,if the control panel is done right it would effectively be a "motor-starter" type of panel. These USUALLY drop out with a power fail.
Stop actually breaks a circuit and start momentarily makes it. The "overloads" are set so momentary overloads don't cause stuff to shit dowm. I've primarily dealt with 3 phase panels. I always wired them with a auto/hand type of switch and start/stop pr was it on/off/manual. I forget.

The deal is that when wired the start/stop way the motor drops out on a power fail which we SOMETIMES didn't want. The three phase stuff also had 3 phase protection, under voltage protection and a start-up delay.
 

Dodgydave

Joined Jun 22, 2012
8,673
Can you tell me how much current passes through the push buttons
If you wire it correctly, the current through the push button should just be the relay coil current, the full motor current will be switched by the relay contacts.

The diagram below is for a 3phase load, single phase is the same but only one set of motor contacts.

7d6edf76851421c67b86f9434550b410.jpg
 

Thread Starter

Niladri Pal

Joined Jun 21, 2017
18
Thanks fr all about the info
But all i want to say that i want replace only thek start stop switch with two relay my relay coils will be driven by a circuit that i made,i want to connect the push buttons in the no pin off the relay so i want to know that what are the volt and amp ratings in the push button pins
 

Thread Starter

Niladri Pal

Joined Jun 21, 2017
18
746 watts = 1 horse power
and picture showing 10Amp current ...

so current will be nearby it...
Thanks fr all about the info
But all i want to say that i want replace only thek start stop switch with two relay my relay coils will be driven by a circuit that i made,i want to connect the push buttons in the no pin off the relay so i want to know that what are the volt and amp ratings in the push button pins
 

Thread Starter

Niladri Pal

Joined Jun 21, 2017
18
I
Well,if the control panel is done right it would effectively be a "motor-starter" type of panel. These USUALLY drop out with a power fail.
Stop actually breaks a circuit and start momentarily makes it. The "overloads" are set so momentary overloads don't cause stuff to shit dowm. I've primarily dealt with 3 phase panels. I always wired them with a auto/hand type of switch and start/stop pr was it on/off/manual. I forget.

The deal is that when wired the start/stop way the motor drops out on a power fail which we SOMETIMES didn't want. The three phase stuff also had 3 phase protection, under voltage protection and a start-up delay.
Thanks fr all about the info
But all i want to say that i want replace only the start stop switch with two relay my relay coils will be driven by a circuit that i made,i want to connect the push buttons in the "no" pin off the relay so i want to know that what are the volt and amp ratings in the push button pins
 

AVINASH_08

Joined Jan 14, 2016
31
Thanks fr all about the info
But all i want to say that i want replace only thek start stop switch with two relay my relay coils will be driven by a circuit that i made,i want to connect the push buttons in the no pin off the relay so i want to know that what are the volt and amp ratings in the push button pins[/QUOTE check and measure current manually by measuring instruments..and match your specifically requirement with available switches..
 

drc_567

Joined Dec 29, 2008
757
... consider this ...
I had a two horsepower, 120 volt air compressor, and was able to measure the motor current from a cold start. For the first few seconds there was a surge of 70 amps, for 5 or 10 seconds maybe, before returning to the rated running current of 15 amps.
... On cool days, when there was extra friction added to the load, the main circuit breaker usually opened. ...Not on a warm day.
...
 

Thread Starter

Niladri Pal

Joined Jun 21, 2017
18
... consider this ...
I had a two horsepower, 120 volt air compressor, and was able to measure the motor current from a cold start. For the first few seconds there was a surge of 70 amps, for 5 or 10 seconds maybe, before returning to the rated running current of 15 amps.
... On cool days, when there was extra friction added to the load, the main circuit breaker usually opened. ...Not on a warm day.
...
Ya but in my case i want to add the relay replacing the start and stop push buttons,so i want the ratings of the push buttons and in this moment i dont have measuring tool to measure the volt and amps so i want to know the push button ratings,is thereany other methods to know that?
 

drc_567

Joined Dec 29, 2008
757
... If the relay is carrying the actual load, then the push button only has to operate the coil current of the relay. ... Maybe that would be 1 amp at 120 volts in the states. Choose a relay that is sufficient to carry the start up transient current, or else there might be difficulties.
 

Thread Starter

Niladri Pal

Joined Jun 21, 2017
18
... If the relay is carrying the actual load, then the push button only has to operate the coil current of the relay. ... Maybe that would be 1 amp at 120 volts in the states. Choose a relay that is sufficient to carry the start up transient current, or else there might be difficulties.
I want to drive that push buttons using relay and relay coils will be connected to the circuit i had maid
 
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