Timer Relay

[Darkness]

Neighbour has two separate augers in his milking parlour and each are controlled by a timer relay switch that are set for 10-15 minutes. One auger is always having problems with the time switch and it has been replaced twice already and has failed again. Seems to last 3 months at most.

The auger works by a switch inside a bin and when the bin's contents drops below the switch, the switch goes into an on state and every 15 mins etc the timer/relay starts the motor if the the switch state in the bin is on. If the bin is full, the motor doesn't start.

Can anyone recommend another timer relay to use just to see if that one is far more reliable?

Because the other auger works fine without issues, could the DOL-Starter on this one have some sort of impact on the timer relay packing up?

Thanks for any input.

View media item 85954
http://www.milkingmachines.co.uk/pdf/Relpol_Multi_Timer.pdf

 

[333rocky333]

Merlin gerin do ones that physical size, dont know part number though sorry

 

[crystal ball]

Have a look at RS or Farnell

 

[Simon35]

Is the other auger identical? Same components, same construction?

Why is the overload hanging off the bottom of the contactor?

Some fusing might be nice to protect the control circuit (timer relay).

Is it subject to high/low temperatures? Water ingress? Condensation?

We always use Siemens control gear on our projects, http://uk.rs-online.com/web/p/time-delay-relays/8316044/ should be suitable.

 

[Darkness]

The other auger is identical. Both were installed at the same time. The overload 'hanging' is identical in the other auger. Both are schneider.

The farmer has other equipment on the farm and they use Siemens kit and all have been excellent in reliability so might try that route.

Fusing is something to think about and overloading the timer could be a cause.

Damp/water isn't an issue due to its location and still had problems in the hot summer days.

 

[Darkness]

I take it theses Siemens relay timers are rated at 16A or above? Can't seem to find anything on the specs unless I am going blind.

 

[RF Lighting]

It looks like the timer is only switching the contactor coil, so the load will be around 0.1A. Any timer will be suitable for this.

 

[stillp]

That overload relay is not the correct one for the contactor. Looks like a Chinese copy. The timer is probably the same. I'd rip the lot out and replace with kit from a reputable manufacturer; Schneider, Siemens, ABB, Moeller, etc.

 

[GNServices]

That overload relay is not the correct one for the contactor. Looks like a Chinese copy. The timer is probably the same. I'd rip the lot out and replace with kit from a reputable manufacturer; Schneider, Siemens, ABB, Moeller, etc.

I didn't notice this but I think you're right,

Does the other timer and contactor that has no problem look the same as this one?

 

[Darkness]

They are the same.

The Schneider starters were supplied by the people that installed the auger and the spark called in to wire it supplied the timers.

 

[Spark123]

What voltage is the coil? The overload doesn't look to be connected properly, it is at a bit of an angle.
I'm assuming it is 400v control, some dol starters have inbuilt capacitors or resistors to drop the voltage for the coil

 

[Darkness]

The coil is 230v.

I'll see if I can get some more photos which include the details that are printed on the side.

 

[stillp]

They are the same.

The Schneider starters were supplied by the people that installed the auger and the spark called in to wire it supplied the timers.

But they aren't Schneider starters! Schneider starters would have Schneider overloads in them.

 

[bernardgreen]

Do you have a circuit diagram of how the timer is connected to the contactor ?

How does the timer fail ? Does it click ( relay operating ) but the output doesn't change ? If so the contacts in the timers have been damaged.

Output Circuit - Contact Data
Number and type of contacts 1P / 1CO (Changeover)
Contact material AgNi
Max. switching voltage 400V AC / 300V DC
Rated Load AC1: 16A / 250V AC
Min. breaking capacity 0.3W 5V, 5mA

What is the coil rating of the contactor ? Do both contactors have similar coils ?

 

[mfarrow]

https://www.google.co.uk/search?q=mt-tua-17s-11-9240

It appears to be the correct part.

As others have rightly said though, premature failure of this nature indicates it is incorrectly rated. It could be the load is higher than anticipated (possible due to a motor 'characteristic' or the supply voltage at the farm is higher than rated for the coil (assuming it's running on 230V mains).

At this stage I would contact the supplier for investigation and resolution. Your timings suggest it's a new installation under a year old, in which case warranty and/or service contracts could be affected by user intervention.