Danfoss 3ph motor inverter causing hot cables.

[netblindpaul]

Engineer54,
Why do you think I started with the 20 questions interrogation!

 

[Crustycracker]

Hi all, sorry about the dissapearing act for a while, working away. Plus I lost my password to the site and couldnt reply to anybody.

Pumps rewired now with SY cable, 16mm 4c. What total b***ards the glands where to make off. Especcially in the inverter box. You cant even wear gloves while you do it. All done according to Danfoss install instructions. Only downer is that I had to install an MCB in the DB but it is a 63A (max permitted with this inverter). But it is barely warm whereas the old 25A one got so hot it crumbled away.
The cables are not in the slightest bit warm. I'll keep my eye on it just in case things warm up but i'm confident it should be ok.
Somebody commented on why were inverters used. The answer is, I dont have a clue. My guess is that the site was over engineered. I also think that whoever requested them probably thought that a soft start was the same item. In this situation the pumps must either run 100% or nowt. If they run at a lower value then we get low pressure alarms. Basically its a crap setup and we have to make the best of what we have, there is no money to rip it all out and start again.

 

[silva.foxx]

Thanks for feeding back.