Testing station and making it safer?

[Practical Goat]

Hi guys,

We have a little test station at work for checking the operation of electrical safety brakes, clutches and electromagnetic coils. The 230 AC all feed into different rectifiers... 24vdc...104vdc.. 207vdc...

It runs off a plug top, max current is about 6A but I'm wanting to make a bit of a more organised arrangement and add some more protection. Could I use a MCB/RCD before all these rectifiers? Maybe some sort of inline fuse?

Thanks.

 

[Spoon]

Hi guys,

We have a little test station at work for checking the operation of electrical safety brakes, clutches and electromagnetic coils. The 230 AC all feed into different rectifiers... 24vdc...104vdc.. 207vdc...

It runs off a plug top, max current is about 6A but I'm wanting to make a bit of a more organised arrangement and add some more protection. Could I use a MCB/RCD before all these rectifiers? Maybe some sort of inline fuse?

Thanks.

Why a MCB? What is wrong with the plug fuse?
If the circuit is not RCD protected you could fit something like this.

or changed the socket to one with a RCD...

 

[Taylortwocities]

Last time I was involved in a bench test set up, we used 10mA RCDs.

 

[Practical Goat]

Why a MCB? What is wrong with the plug fuse?
If the circuit is not RCD protected you could fit something like this.

or changed the socket to one with a RCD...

No reason dude. Just wanted it to trip first for resetting purposes.

 

[Spoon]

No reason dude. Just wanted it to trip first for resetting purposes.

I'm presuming this reply is for my "Why a MCB? What is wrong with the plug fuse?" question.
The plug fuse should always blow before the circuit MCB trips.

 

[Practical Goat]

I'm presuming this reply is for my "Why a MCB? What is wrong with the plug fuse?" question.
The plug fuse should always blow before the circuit MCB trips.

It is yes. Thank you. Just wanted to check that the plug fuse is an acceptable primary failsafe. Often the equipment can have faults that we test.

 

[Spoon]

It is yes. Thank you. Just wanted to check that the plug fuse is an acceptable primary failsafe. Often the equipment can have faults that we test.

What type of faults mate? Things that RCD will solve or things that blow the fuse?
I wouldn't want to keep replacing the fuse in the plug all the time. I would fit a box with a reset fuse. (pop-up fuse... or whatever they are called)

 

[SparkyChick]

What type of faults mate? Things that RCD will solve or things that blow the fuse?
I wouldn't want to keep replacing the fuse in the plug all the time. I would fit a box with a reset fuse. (pop-up fuse... or whatever they are called)

Something like this maybe....

W54-XB1A4A10-5 | TE Connectivity 5A 1 Pole Thermal Magnetic Circuit Breaker, 250V ac W54 | RS Components - https://uk.rs-online.com/web/p/products/7828035

 

[Practical Goat]

It's rare, but sometimes the rectifiers can be faulty and also the coils. We test them for continuity but sometimes they are partially shorted and pop the fuse. It's not often at all. Just wanted it to look neater and more professional really.

 

[davesparks]

Why not test for faults before energising things?

 

[shaun1]

Why not test for faults before energising things?

I would agree that this should alway be step one of any test. You could add some kind of ohmmeter to the bench and a list of resistance measurements for each type of device to be tested.

 

[davesparks]

It's rare, but sometimes the rectifiers can be faulty and also the coils. We test them for continuity but sometimes they are partially shorted and pop the fuse. It's not often at all. Just wanted it to look neater and more professional really.

If you test continuity why don’t you test for faults at the same time?

 

[Practical Goat]

I always test them for faults. Both the resistance of the coil and to ground before i switch on. The other guys sometimes don't however..

 

[Practical Goat]

If there are anymore tests I should be doing. Please do let me know. I purposely posted this on the DIY section to allow for any uncertainty in what I'm saying. I test all the diodes with the continuity setting then energise all bridge and half wave rectifiers - then test the voltage drop across each diode... i then check the output is a smooth DC with the scope and the coils for the manufacturers ohm +/- 10%..

I also probe the body of the safety brake and put it to earth and see if I have any obvious faults with low resistance.

We have just been wanting to make this little rig the right way, both to look, act and behave safely. Im primarily from an electronics background so I'm under no illusion my electrical industry skills are a bit s**t.

 

[davesparks]

I always test them for faults. Both the resistance of the coil and to ground before i switch on. The other guys sometimes don't however..

I realise it’s a lot easier said than done, but my initial reaction to this is to say that more training and/or stricter procedures are required.