Circuit Protection - Variable Speed Drives

[Garmy1]

Hi All,
I have just joined and this is my first post, so apologies if this topic is already covered elsewhere.....
My question is regarding downstream circuit protection on variable speed drives.

I have just installed a fused switch disconnector downstream of a 185kw variable speed drive. The reason being, beacause the original supply cable to the motor was installed in 150mm2 SWA making it very difficult when replacing failed motors, due to the size and lack of flexibility of the cores. So I have changed the installation, the SWA now runs into a large junction box and into a fused diconnector and then tri-rated cable into from the switch, through flexible conduit, and into the motor. (the motor size is 140kw)

Can I operate with fuses downstream of the drive and would it cause problems with the drive if fuses fail?

Thanks

 

[ScottyUK]

Replace the fuses with links. If a fuse blows under load then you will likely be in the market for a new drive or an expensive repair.

 

[Skogsgurra]

As Scotty says.

The protection is built into the drive (can be set via the operator's panel) and will protect both drive AND Cables. No need to put in extra fuses.

But make sure that the protection is correctly set.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[itsmoked]

Welcome to Eng-Tips Garmy.

Let me suggest in the future, a better place for questions on motors and their controls would be in forum237.

Cheers.

Keith Cress
kcress -

http://www.flaminsystems.com