Remote controlling star delta starter

[holmslaw]

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[ColJack]

what do you define as a "hold on coil"?

contactor Q11 holds itself on with one of it's auxiliary contacts once it's operated..

 

[matt1e]

So coljack and matt, if there is no hold on coil, how can the equipment operate?

It cant mate is your answer and agree with you Q 11 does preform the the function as you describe
in my earlier post I was agreeing with coljack on his definitions

In A later post

what do you define as a "hold on coil"?

contactor Q11 holds itself on with one of it's auxiliary contacts once it's operated..

and that's exactly how I would describe it too

Q11's primary function is to drive the motor , it self latches via its Aux contacts as coljack describes, I would class that as a secondary function

the relay K2 I added is designed to latch as its primary function
the contacts are performing secondary functions,
so i personally would describe this as a" hold on" coil
as coljack says " its how you define it
dont worry I agree with you too holmslaw
its just I cant fault coljacks description either, as its how I would describe it too
Padantic is the word i'm looking for methinks

 

[holmslaw]

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[matt1e]

Q11's primary function is to drive the motor , it self latches via its Aux contacts as coljack describes

Q11's (the hold on coil) primary function is to maintain the control circuit (via the hold on contact) to allow the delta contactor to feed the motor. There is nothing latching to any thing.

No Q11 feeds the motor then electrically self latches/holds because its aux contact back feeds the control circuit to its coil
Q13 (star) and Q15 (delta) purposes are to configure the windings into star or delta depending of the position of the timer relay K1

the relay K2 I added is designed to latch as its primary function

It is not, it holds (not latches) the contact for the delta relay in the closed position.

firstly relay latching and relay holding circuits are one and the same thing. latching relays are different things but no-ones talking about them
secondly K2's primary function is to electically latch and bring the remote contact into circuit when start is pressed when the switch is in auto postion, then unlatch when stop is pressed, it has nothing whatsoever to do with the delta contactor (or relay as you seem to be calling it)
But hey what do I know? I just sat and designed the mod for the circuit posted!!

Padantic is the word i'm looking for methinks

The word is pedantic, commonly used by contractors when their errors are being explained to them.

spelling mistake .... I'm guilty as sin!

There's a massive difference between a hold on circuit and a latching circuit, as I pointed out in my original post.

This doesn't sound right to me.

The only time you would use latching relays on mechanical equipment would be if the dangers of the equipment stopping outweighed the dangers of it continuing to run. Also if the control circuit fails the pump will continue to run, how can you turn it off? via a local isolator? is it designed to be opened on full load current. And after a power failure the pump will auto re start.

Also the schematic does not show any mechanical interlock on the star delta contactor.

where have you pointed out the difference between latching circuits and holding circuits?
as said earlier a relay latching circuit is not the same thing as a latching relay
we could argue the difference between a relay and a contactor if you like

I'd be doing a bit more investigating before fiddling with the controls, it all looks a bit dodgy to me. Did the farmer design the cortrols? icon_smile.gif

your last paragraph shows your understanding of the circuit, as said, its a bog standard control circuit for star/delta motor starting

Matt

 

[matt1e]

here's the motor circuit if you want to study it
I've marked up the contactors
View media item 29135
Matt

 

[holmslaw]

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[matt1e]

Why would I study a schematic drawn by someone who things latching and hold on are the same thing?

1) I didn't draw it, it was pasted from another source
2) relay latch circuit,
relay hold on circuit,
relay self maintaining circuit,
relay self sustaining circuit

I think these are all the same thing too, and I'm not the only one that thinks it's called a latch circuit read 7-4-2 (but I doubt you will)

Next you'll be telling me a neutral link and a fuse link are the same thing

No, they're not (apart from both being termed links) so why would I?