Sizing cables for Dc Motor application
Sizing cables for Dc Motor application
(OP)
Hi i am re-installing a large machine at the moment
the dc mator is 570 amp F.L.C (300vdc)
the problem is this motor had its feed cables replaced
about 6 months ago and they went on fire about a month ago. I am reluctant to use the same cable again ,there are 2 terminals on the motor each terminal has 3 of 70sq cables terminated.(the cables have only about 1mm of insulation) any assistance would be appreciated
the dc mator is 570 amp F.L.C (300vdc)
the problem is this motor had its feed cables replaced
about 6 months ago and they went on fire about a month ago. I am reluctant to use the same cable again ,there are 2 terminals on the motor each terminal has 3 of 70sq cables terminated.(the cables have only about 1mm of insulation) any assistance would be appreciated





RE: Sizing cables for Dc Motor application
If done in this way there should be no particular hazard even for a full ground fault. I've seen those happen as when brush springs come loose and ground the armature circuit and, will it results in a huge flash and usually a damaged drive, the cables are undamaged.
RE: Sizing cables for Dc Motor application
DickDV has offered some good advice. You need to take a closer look at your cable sizing calcs, as the existing arrangement appears to be marginal.
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If we learn from our mistakes,
I'm getting a great education!
RE: Sizing cables for Dc Motor application
For the size of motor that you have this would be cheap insurance.
I onetime went to clean a 4 pole motor and discovered that one of the brushes had popped loose causing only 1/2 of the armature to carry current. I put in a work order to the effect that the motor had been in slow cook mode and needed to be replace Real Soon Now. Sure enough, about 1 month later the motor burned up.