- Joined
- Feb 2, 2013
- Messages
- 3,627
My 2 cents...
There is absolutely nothing wrong with using a magnetic contactor as your power cut off.
the VFD has no idea what the cutoff device is or how it's wired in and really doesn't care as long as power is uninterrupted to the VFD during it's intended operation.
A contactor is the primary means that larger hp motor operating currents are switched on and off.
I have 30 Packaging machines that get their source of power from a circuit that is directly supplied with power from magnetic contactors and have not had a single failure from their use.:thumbzup:
the 30 food packaging machines have been in continuous operation for 10- 14 years if that makes you fell any better......
Their thinking may be as a safety precaution should the contactor's contact tips should weld together, there would be power flowing through the contactor even if the contactor's control circuit was de-energized.
But if you were to wire in an overload relay, it would provide an excellent way to provide as much safety as possible and still accomplish what you wish by using a magnetic contactor.
There is one other alternative i could suggest that is quite cost effective and even simpler to install...
an emergency stop switch....
there are many manufacturers of switches for that purpose. I use a lot of Telemecanique and Square D
the only draw back is the E-Stop switches are for control purposes and generally can't carry much current.
but they can be used in conjunction with the contactors control circuit and provide a higher degree of safety as well, should you wish to entertain that type of circuit.
i can help you with the project if the need arises, shoot me a PM if i can assist in any way.
mike)
There is absolutely nothing wrong with using a magnetic contactor as your power cut off.
the VFD has no idea what the cutoff device is or how it's wired in and really doesn't care as long as power is uninterrupted to the VFD during it's intended operation.
A contactor is the primary means that larger hp motor operating currents are switched on and off.
I have 30 Packaging machines that get their source of power from a circuit that is directly supplied with power from magnetic contactors and have not had a single failure from their use.:thumbzup:
the 30 food packaging machines have been in continuous operation for 10- 14 years if that makes you fell any better......
Their thinking may be as a safety precaution should the contactor's contact tips should weld together, there would be power flowing through the contactor even if the contactor's control circuit was de-energized.
But if you were to wire in an overload relay, it would provide an excellent way to provide as much safety as possible and still accomplish what you wish by using a magnetic contactor.
There is one other alternative i could suggest that is quite cost effective and even simpler to install...
an emergency stop switch....
there are many manufacturers of switches for that purpose. I use a lot of Telemecanique and Square D
the only draw back is the E-Stop switches are for control purposes and generally can't carry much current.
but they can be used in conjunction with the contactors control circuit and provide a higher degree of safety as well, should you wish to entertain that type of circuit.
i can help you with the project if the need arises, shoot me a PM if i can assist in any way.
mike)
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