Siemens SITOP primary fuses.

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Thread Starter

Anthony Kerstens

I'm looking at using a Siemens 40A 24VDC power supply with 3ph 400-500VAC input.

The documentation recommends part numbers for a characteristic C CB. I am required to use fuses.

For 1060W at 480VAC, would anyone have experience verifying what the fuse should be?

I am tempted to use a 2.5A class J time delay fuse.

Anthony Kerstens P.Eng.
 
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Hi Anthony,

According to Siemens catalogue for Sitop Power 40A 6EP1437-2BA10 protection you should use: miniature circuit breaker up to C25 (C6
recommended) or motor circuit breaker, for example Siemens 3VU1300-0MJ00 or 3RV1021-1DA10 current setting=3A

I hope this helps
Jarek Klak
 
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It's me again. I overlooked you were required to use fuses. You don't need to worry about overload protection I belive. Sitop has internal electronic secondary current limitation. And for
short-circuit protection purposes it's better to use 6A slow fuses. You may have problems with 2.5A due to power-on inrush current.

Jarek Klak
 
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Anthony Kerstens

Thanks. I've looked at Gould slow blow curves. A 3A fuse on the curves I've provided would trip at 50A after 100ms. Fuses between 4A and 6A would trip at between 80A and 90A after 100ms.

The guy at Siemens (Germany) that I've emailed to indicated that a characteristic C circuit breaker set at 6A would trip at 60A after 100ms.

He is quite adamant that fuses not be used, and I don't understand why. And I'm required to use fuses (by my customer).

Anthony Kerstens P.Eng.

 
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