Starting Current Calculation

With what starter?? DOL or S/D?

You can find information on "www.moeller.es/descarga.php?file=public/142/MSC.DS..."

Regards

The locked rotor current is the supply voltage divided by the resistance of the supply cable and the resistance of the winding it is applied to.

The motor nameplate will give the FLA (full load amps) or FLC (full load current) of the motor. Another item on the nameplate will give a code letter that tells the ratio of starting current to FLA/FLC. Multiplying these values gives the starting current of the motor. What you need to do is not so much a calculation, but rather a look-up of the motor data.

Why dont you use Softwares like Etap, Power Digsilent. You can find easily start current.

Hi Guest,

The motors' starting current varies differently from motor to motor, as evidence; you sometimes find two motors of two different manufacturers with the same power ratings, but their starting current is dissimilar… in conclusion, there's no general rule…………

Regards,

it is normally taken as multiple of Coded letter on name plate or if you dont have any thing take 6-- 12 times FLA

dear ,

You want to find the starting by calculations ? not by refering the manufacturer's guide ?

Motor starting current = V line - line /1.732*Zsc

where Zsc = Impedence of the motor as referred to stator

winding.

Motor starting on DOL

starting current = 4-8 times full load current. Typically taken as 7.5 times FLC

Starting Torque = approx full load torque

Motor Starting on Star-delta

starting current = 1/3 Starting current of DOL = approx 2.5 times FLC

Starting Torque = approx 33% of full load torque

Motor Soft Starting

starting current = depending on setting (>150% onwards of FLC)

Starting Torque = Depending on the current limiter setting may be as low as 6% of Full load torque.

Motor Starting on VFD

Depending upon