Preventing AC motor restart.

Robert wrote:


The question that no-one has yet asked is about the specifics of the motor and its internal protection.
If your motor is a smaller type then I can understand that the sensor may be in series with the power feed to the motor. If this is the case then a current sensing relay would certainly be the item you need.
I deal with systems that have some quite large motors and these have separately wired sensors which we can bring back to the motor control units and utilised to interlock the starter circuit. This is usually the province of the larger multi-phase motors whose starter arrangements are more complex.
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It is a fractional HP single phase 120 VAC motor. One in each of your hands is not a problem. From what I have been told, the running current is from 1 to 10 amps depending on load. The over temperature device is internal and automatically resets. I assume it is a snap action device in contact with a winding.
The information that exist in house is held by people how do not understand the need for information to flow. The old "information is power" idea does not even fit. They do know what is on the paper in front of them, so into the trash it goes.
In a different life I had the fun of getting a 50 HP DC motor to track the speed fluctuations of a 150 HP DC motor. The idea was to get them to ack like gears connected their shafts for a process that resembled thread cutting. Managed to get it to work and ended up with a gread deal of respect for Seimens controlers.
I hope everyone is having a good day, Robert H.
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Good morning,
Whether following as the happen, or reading long after the fact, I appreciate usenet threads that have a ending.
My focus had been on electromechanical devices. Fortunately, those in control have backed away from 80 C ambient. I am back into a temperatur range that can be met with commonly available items. An electronic current sensor, a relay to handle the load, and a momentary switch to get things started.
I offer my thanks to those who offered thoughts and information on this subject. While ranking the responses is inappropriate, the term "amperometric relay" from another newsgroup does stand out.
A good day to all, Robert H.
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