Hi DanDel!
Please note that the 'kva per hp'given in the equation is the locked rotor kva, as defined in NEC. The letter / alphabet given on a motor can be used to determine the kva per phase. e.g. Letter 'A' means 0-3.14 kva/hp.
Hope it will clarify.
God bless.
mta2003
Hi!
I think separate LRA protection is the best option, specially when starting current is very high and lasts for longer time due to high inertia e.g. large fans.
In such case if the thermal over load is set at higher value than the normal full load rated current then in case of a faulty...
Hi!
The locked rotor current is usually the starting current and is 6 to 7 times higher than the normal rated current.
The formula for calculating LRA is:
LRA = kva per hp X hp X 1000 X 1/k X 1 / line volts
value of "k" is 1 for 1-phase, 2 for 2-phase and
1.732 for 3-phase.
The LRAs are...
Dear Yokohama!
As the developement in the field of power electronics is very fast and availability of spare parts of a 15 year or more old equipment is a real problem, therefore replacement of such older equipment is very economical and useful.
God bless.
mta2003
Dear Suntop!
Please don't get disturbed by the response of jghrist. He was trying to help you. As you must be aware that all panels are according to some standard e.g. BS, DIN / VDE, IEC, IEEE or JiS etc. For qualification, some type tests are essential on proto types which is a costly affair...