SparkyKris

Hi,

A brief introduction: I work in a factory that manufactures heating elements. We have testing stations that the operators would put the elements on to test. These testing stations are basically a control panel (method of controlling various voltage outputs from 0Vac to 400Vac, using either variable transformers or via thyristor control) a transformer and a test bed (caged test area where the element sits on top of conductors made of a mixture of carbon blocks and aluminium braided wire)

The operators would put the elements on top of these contacts (either between phase and neutral or between phase and phase), shut the cage gate and remove the safety key. Insert the safety key into the panel interlock to activate the control panel. The control panel lets the operator start the power output and adjust the output to the voltage (0-400Vac) selected for the element, with the feed back of voltage and current panel meters.

The operator would set the test to the desired voltage and wait until the current settled, then read the current reading therefore the rating of the element.

I wish to improve the safety of these machines by installing a test lamp circuit so that after the test is complete and the operator removes the interlocked safety key from the panel he/she can be assured that when he/she opens the cage gate there is no live conductors within that cage that may cause them harm while trying to remove the tested element.

My trouble is that normally I would use a test meter to check for voltage and not a test lamp, so I'm not familiar with the voltage range of these devices and also if anyone has any ideals of a circuit or devices I can use - they would be very welcome.

Thanks in advance if there is any help you can give me..

alan

On these sort of circuits, one normally have a main contactor that feeds the element circuit. If so put a n\c aux contactor on this, which is fused and connected to a suitable voltage. When the main contactor makes the lamp lights to indicate that there is power to the element.

ian.settle1

If I understand your question, you put it across the same connection from the contactor to the element.

rumrunner

Hi Kris
I would use the n/c contact method as described above,if there is not one spare on the contactor consider adding a relay
all the very best in the world
chris