roller shutters

[tazz]

Yes but the N/C limit switch will be on the wrong relay/contactor coil.
So if the motor is running the wrong way (phase rotation wrong), then the wrong limit switch will be operating on the de-energised coil and will not stop the shutter.

See you point, so hopefully a OL trip

 

[Jonesy83]

Get me some details on motors and controls and I maybe able to help pics would be advantage are they single phase or 3 phase most likely single phase tube ops on windows are they individually controlled or on a group command

 

[Outspoken]

Yes but the N/C limit switch will be on the wrong relay/contactor coil.
So if the motor is running the wrong way (phase rotation wrong), then the wrong limit switch will be operating on the de-energised coil and will not stop the shutter.

That I do not get, whenever I have wired up roller shutters or similar equipment that has upper and lower limit switches I have always wired up the upper and lower switches in series with the E-Stop via a N/O (no-volt) contactor so if any of the three are operated the contactor coil loses power, releases and stops the motor drive dead in it's tracks..I do not get why you would wire in multiple circuits for the control of something so simple.

And the above is true for either single or three phase units. The phase the E-Stop/limit switches is on should be totally irrelevant all control circuit cabling should be on the same phase and the way that is connected at the motor or even the isolator should be totally irrelevant as well.

 

[Jonesy83]

Depends on the motor if its a single phase tube op motor then limits will stop as its a simple circuit but in a case of a 3 phase motor if the phases are reversed then the limits will also go to cock so it will ride past the top limit or lower limit

tube op limits are renowned for the limits moving or going faulty need more info of the op as he hasn't stated wether 3 phase or single phase also if there operated in a group or single and if in a group and how much of the wiring he's worked

 

[Knobhead]

That I do not get, whenever I have wired up roller shutters or similar equipment that has upper and lower limit switches I have always wired up the upper and lower switches in series with the E-Stop via a N/O (no-volt) contactor so if any of the three are operated the contactor coil loses power, releases and stops the motor drive dead in it's tracks..I do not get why you would wire in multiple circuits for the control of something so simple.

And the above is true for either single or three phase units. The phase the E-Stop/limit switches is on should be totally irrelevant all control circuit cabling should be on the same phase and the way that is connected at the motor or even the isolator should be totally irrelevant as well.

With the limits in series how do you get the shutter off the limit? If it’s up it won’t go down.

Cranes will have a top and bottom limit, one in each action. There would also be ultimate limits these killed all movements, they would be fitted with a “back out” switch under the control of the electrician.