Lift Supply

[novolts]

Hi Guys
I was called to fault with a socket in a lift motor room the other day
I noticed that the lift was isolated by a 3 phase switch fuse
I thought this a bit odd because if one of the fuses ruptured it would leave a lift with 2 fuses possibly casing damage to the lift motor and controls
My thoughts are that instead of a 3phase switch fuse it should be a triple pole circuit breaker
thoughts would be appreciated
kind regards
novolts

 

[MDJ]

Hi Guys
I was called to fault with a socket in a lift motor room the other day
I noticed that the lift was isolated by a 3 phase switch fuse
I thought this a bit odd because if one of the fuses ruptured it would leave a lift with 2 fuses possibly casing damage to the lift motor and controls
My thoughts are that instead of a 3phase switch fuse it should be a triple pole circuit breaker
thoughts would be appreciated
kind regards
novolts

Before replying I have a question for you, before triple pole breakers were invented and only fuses available how did these lifts in hotels around the world cope with 3 seperate fuses in a switch fuse?

 

[Plonker 3]

Lots of 3 phase switch fuses all over the country with similar set ups. Especially in factories where machines will be used.

You do know why they use HRC fuses dont you?

 

[Knobhead]

There's a relay in the panel that takes care of this.

Now try looking for what it is.

 

[Pete999]

Most three phase FUSED units have a device that, should one fuse rupture then the three phase supply is completely disconnected sometimes via a striker arm which trips a relay of some sort, long time since I dealt with that sort of thing, so things may have changed a little in this solid state world we live in today

 

[MDJ]

So much for my question to the OP lol

 

[Pete999]

Sorry mate just can't help myself sometimes come with age or so they tell me, doubt very much if he would have answered you anyway lol

 

[benji]

check manufactures spec. i think the likes of OTIS spec. sw.fused isolators

 

[i=p/u]

Think the modern is triple pole mcb straight to panel which the door open isolates panel

 

[Knobhead]

Think the modern is triple pole mcb straight to panel which the door open isolates panel

2[SUP]nd[/SUP] time in two days.

Think again.

 

[tazz]

Most feeds I have done in the past have been 3 phase switched fused isolators, with a very serious reason....They can be lock off with the lift engineers own padlock, to stop Electrical Trainee switching them back on, when the poor engineer is in the shaft.

 

[bossian]

Modern 3 phase machinery these days, with DOL or star/delta, will have a phase failure relay fitted in the start circuit to prevent motor start if a phase is lost. The three lifts at my place have this prevention in place.

 

[gnuuser]

Modern 3 phase machinery these days, with DOL or star/delta, will have a phase failure relay fitted in the start circuit to prevent motor start if a phase is lost. The three lifts at my place have this prevention in place.

ha ha reminds me of when a fuse blew on the batch tower elevator at our plant.
panel was up in the hoist house at the top of the batch tower.
had to climb the access ladder outside the tower (100 feet plus)
batch can attendant stuck in elevator swearing up a storm (quite amusing actually)

 

[Knobhead]

You wouldn’t laugh if it was you stuck in the lift. Four bloody hours sat on my helmet in an ice cold steel box 250’ up. The alarm didn’t work nor did the rescue phone, against works rules I’d got my mobile.

There were repercussions:
On site we had one person trained in lift rescue, ME!
We had a few more trained up after that.
I was carted of to hospital to thaw out, I was close to hyperthermia.

 

[novolts]

Thanks to all that replied to my post
I am not up to date with all the jargon
so MDJ when you have time and you can be bothered what do you mean by OP
thanks
novolts