DC Motor leads Chart

[petronila]

Dear All,

Looking for a lead chart for DC motors based on Amp and temperature rating.

Thanks in advance

Petronila

 

[edison123]

Not aware of a lead chart. I always try to improve on OEM lead size if there is space. Have even provided with new and modified motor TB's to accommodate the leads per clients' requirements.

I have found OEM's generally use 3-5 A per sq mm but have seen some use as high as 10 A per sq mm.

Muthu

http://www.edison.co.in

 

[Gr8blu]

petronila Once again the lack of a "standard" rears its head. How much current a specific power lead can handle is dependent on both the original equipment manufacturer (including when it was made, what insulation is on the conductor, whether the conductor is cable or bus, etc.) and on where the conductor is routed (does it go to "free air", or an enclosed space such as a terminal box? Are there multiple conductors in close proximity? How high is the local ambient temperature? etc.) and lastly - is the machine itself separately force cooled (or does it rely on a shaft mounted fan)?.

As a rule of thumb, force-cooled designs using modern (EPDM insulated) cable will typically operate in the 3-5 A/mm2 range. Bus may be a bit higher. If there are a lot of cables in parallel passing through the frame and ending up in an enclosed (non-ventilated) terminal box, the best course is to be near the lower end of the typical range because of proximity effects when the cables are "bundled" (to the point where they are usually touching each other) into the available space.

Some manufacturers have also "derated" their conductor capability if they know in advance that the power source is to be an electronic supply (e.g., a 6-pulse thyristor type drive) to offset additional heating from harmonic currents.

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