Vfd

John robertson · Aug 19, 2021

I've not worked with vfds before but have been asked to add an emergency stop button and a level sensor. Looking at the manual and reading other things online im little confused. For the emergency stop am I right in thinking i just want to break the control voltage 24v? So would i just put the em stop in series with the control terminals? The manual has 24v output terminal and things i have read say i can put the em stop in the digital input terminal, which one is correct? And would the level sensors then get connected to analog output terminals? I might be completly wrong what i said so apologies. Might be a case of turning down the job as I dont want to damage any equipment.

James · Aug 19, 2021

Generally speaking, an emergency stop should remove all sources of energy from the machine.
it is permissible to leave a control voltage powered up.
Simpley removing the drive run signal from the vfd is unlikley to provide adequate safety protection.

Spoon · Aug 19, 2021

If you are going to use an "Emergency Stop" then you need to do a risk assessment and find out what category of stop you need.
If you just need a "Stop" button then that is simpler.
You will also need to know what exactly you want to do when pressing the stop, like you you want the motor to free wheel to a stop or do you need to stop it quickly.

John robertson · Aug 19, 2021

Spoon said:
If you are going to use an "Emergency Stop" then you need to do a risk assessment and find out what category of stop you need.
If you just need a "Stop" button then that is simpler.
You will also need to know what exactly you want to do when pressing the stop, like you you want the motor to free wheel to a stop or do you need to stop it quickly.

The guy running job is from the mainland, I stay in western isles, but he said and emergency stop, so Im assuming he has done all the risk assessments. I have just spoken to him through email. So im unsure what he needs. I will need to try contact him tomorrow and find out.