Shunt Trip Breaker on Elevator

[jimmyjam]

Can anyone give me information on wiring a shunt trip breaker with 120 volt coil. I think the 24 volts from the fire alarm system will tie to a 120 volt relay with 24 volt coil and when the alarm goes off it will power the coil and close the 120 volt coil and trip breaker to elevator. can anyone help me with this.

 

[hysticali]

You have it right, the fire alarm relay will close allowing 120v to trip the elvator breakers. The 120v circuit must also be monitored by the FACP, in case someone accidentally turns off that breaker. Elevator breakers should not be able to be reset until Fire Alarm is reset.

 

[hurk27]

Can anyone give me information on wiring a shunt trip breaker with 120 volt coil. I think the 24 volts from the fire alarm system will tie to a 120 volt relay with 24 volt coil and when the alarm goes off it will power the coil and close the 120 volt coil and trip breaker to elevator. can anyone help me with this.

You are going to need to contact the elevator company, I have never heard of shunt tripping an elevator when a fire alarm goes off, this would or could trap people in them and would risk their lives, in most elevators I have ever seen, the cab returns to the designated floor and stops all floor commands till fire key switch override is used.

 

[adelle]

Another Idea

Another Idea

How much current is available from that 24volt trigger? And how much current does the shunt trip coil need?

If there's a safe match, you could back feed an HVAC control transformer.

P.S. I am assuming the 24v is AC and not DC.

 

[adelle]

You are going to need to contact the elevator company, I have never heard of shunt tripping an elevator when a fire alarm goes off, this would or could trap people in them and would risk their lives, in most elevators I have ever seen, the cab returns to the designated floor and stops all floor commands till fire key switch override is used.

I thought that was done with a gravity brake or slow release valve in a hydralic system.

 

[iwire]

This needs to be answered at a local level, the rules change a lot from area to area.

Elevator 're-call' is a separate issue than the shunt trip on the feeder requirement.

In a perfect world the smoke detectors cause an elevator re-call long before the heat detector trips the shunt trip feeder.

But in RI for example they have had us do away with the shunt trips and just leave the recall system in tact.


Check with the local AHJ(s) about how to handle this at your location.


To throw more complexity into it some hydraulic elevators will automatically 'recall' if the feeder is tripped. (They utilize a small UPS to open the down valve and open the doors when it gets to the recall floor.

 

[hurk27]

This needs to be answered at a local level, the rules change a lot from area to area.

Elevator 're-call' is a separate issue than the shunt trip on the feeder requirement.

In a perfect world the smoke detectors cause an elevator re-call long before the heat detector trips the shunt trip feeder.

But in RI for example they have had us do away with the shunt trips and just leave the recall system in tact.


Check with the local AHJ(s) about how to handle this at your location.


To throw more complexity into it some hydraulic elevators will automatically 'recall' if the feeder is tripped. (They utilize a small UPS to open the down valve and open the doors when it gets to the recall floor.

Guess I didn't even think about a hydraulic type elevator:roll:

Around here most are old cable and pulleys that are counter weighted so the car does not move without power, at least I think it won't?

Of the few hydraulic elevators I have done, we only supplied a disconnect to the shaft, and the elevator company did the rest.

so if the power is cut, what is the purpose of the fire key? it would seem this is defeated when power to an elevator is cut?

 

[iwire]

Guess I didn't even think about a hydraulic type elevator:roll:

Around here most are old cable and pulleys that are counter weighted so the car does not move without power, at least I think it won't?

If you could get a cable elevator to move via gravity (and with the worm drive gear boxes they use that is unlikely) an empty car would go to the top.

Of the few hydraulic elevators I have done, we only supplied a disconnect to the shaft, and the elevator company did the rest.

We provide the feeder, tie it but that is it.

so if the power is cut, what is the purpose of the fire key? it would seem this is defeated when power to an elevator is cut?

The way it is here, smokes on each landing and the top of the shaft will trigger a 'recall' and the key will be effective for fire fighters use.

If the fire progresses and trips a heat detector in the machine room or top of the shaft the car stops where it is if it is a cable type car. If it is a new hydraulic it may go down to the recall floor and open the doors.

I have no idea why they would want the shunt and like I said in RI they have been having us disconnect the shunt trips, one local elevator inspector called an elevator with a shunt trip a 'coffin hanging from a rope' I have to agree with that.

 

[dhalleron]

I run into some inspectors that want to initiate recall before the shunt trip. And the fire alarm code mentions a time delay in the annex section for shunt trip to allow time for the recall to happen.

I've also read that part of the reason for shunt trip is not just because of the power getting wet, but to prevent the braking system from getting wet and allowing a free fall.

There is a decent amount of information in a pdf file on the IEEE website on elevator recall and shunt trip.

http://www.ewh.ieee.org/r3/atlanta/ias/Interfacing_Fire_Alarm_and_Elevators.pdf

 

[dhalleron]

I run into some inspectors that want to initiate recall before the shunt trip. And the fire alarm code mentions a time delay in the annex section for shunt trip to allow time for the recall to happen.

I've also read that part of the reason for shunt trip is not just because of the power getting wet, but to prevent the braking system from getting wet and allowing a free fall.

There is a decent amount of information in a pdf file on the IEEE website on elevator recall and shunt trip.

http://www.ewh.ieee.org/r3/atlanta/ias/Interfacing_Fire_Alarm_and_Elevators.pdf

Pages 71 to 75 gives some example wiring.

 

[luckylerado]

Here is the skinny.
Add a 120v dedicated ckt for shunt trip control wiring. The shunt doesn't draw much so a 15 amp will do.
The fire alarm contractor should supply a set of normally open contacts controlled by the fire alarm panel. Send 2 conductors from here to the shunt trip device. You have now put a single pole switch in line with the load ie the shut trip breaker.

Shunt tripping is only required when you have sprinklers in the pit, shaft, or control room and is triggered only by the heat detectors that are in proximity to the sprinkler heads that protect these areas. The heat detectors should be set to go off right before the sprinkler head and then shunt the elevator.

When smoke is detected in these areas the elevator will go into recall mode and return to the designated floor, open up and shut down.

Presumably, smoke will be detected before heat detectors and allow anyone on the elevator time through the recall function to exit the car before it has been shunted. And before a shower.

A couple other tips for elevators. Make sure that you have overcurrent protection in the control room and that your disconnect is in the right place. A good rule of thumb is no more then one step into the room. Make sure that it is lockable, and if there is an emergency let down system installed for the elevator; a set of contacts that is inter-locked to the disconnect is required.