Roller Shutter Door Safety Cutouts?

[boltonsparky]

Been to a job today, a commercial kitchen that has a roller shutter door between the kitchen and dining room serving hatch.

The roller shutter door had stopped working altogether, they'd had a play with it and basically messed it up (going down with the up button and vice-versa, wouldn't automatically stop at the top or the bottom).

Got it working the right way and adjusted the stop switches so it automatically stops at the top and the bottom.

There was in the motor box 2 cables wrapped up with brackets on the end going into a box on the side of the electric motor and then out to the control circuits on the back of the motor. They are damaged and don't look like they've ever been connected to this door (it is quiet likely at this location that it is a second hand door or motor mechanism)

My question is what are these cables and levers for? My suspicion is they are some kind of load switch that cuts the power if there is something or someone trapped in the roller shutter during lifting or closing of the shutter, are my suspicions correct and is there a reg somewhere that means there has to be an emergency cutout in the event of someone being trapped?

They are not part of the manual override mechanism for if the motor fails this is a separate unit. 

 

[Marvo]

Could be a load safety switch, maybe also a thermistor to stop the motor if temperature gets too high.

Do you have the make and model number of the shutter system?

 

[boltonsparky]

The cables are similar to the cables you have on a pedal bike for the brakes and gears and have a damaged lever on the end, they aren't attached to anything just coiled up and I can't see anywhere they could have been installed and removed from...looks like they've never been fitted on this shutter

I'm going back later this week to do something else so I'll get a picture.

The only branding was a sticker on the motor, KABA, thought they just made high security locks and door entry systems but looks like they make shutter power units too.

The motor does get quite warm after a few ups and downs of the shutter I noticed.

 

[Steve3948]

Is it a cable or a wire for disengaging the gearing on the motor.

My roller doors have magnets top and bottom for limits, and an eye bolt at the top for raising and lowering by hand.

 

[Marvo]

If it's a mechanical type cable then, as Steve says, more likely either to drop the shutter quickly in an emergency or to manually raise in case of power fail. I wouldn't worry about the motor getting warm as long as it doesn't get too hot to keep your hand on it or doesn't start smelling like hot plastic / varnish. These types of motors are often only rated to low duty operation such as 10 cycles per hour or a small percentage of operating time so if you run it several times in quick succession it will heat up quickly. I'd ask the owner for the user documentation or the company details of the installers, these domestic shutters are fiddly to work on at best, I've seen them use phase angle monitoring for safety and limit sensing, also some use a tacometer/basic rotary encoder to establish limits.