Motor starting current limits - IEC 60034-12
Motor starting current limits - IEC 60034-12
(OP)
good morning, I have the following problem with the selection of an electrical motor.
One of the customer requirements is that the figure Is/In (starting current, nominal current) has to be less than 6.5. My customer says that this is required to be in accordance with IEC 60034-12.
My supplier (well-known international motor manufacturer) offered a motor and this value is stated in the data-sheet, the figure is 7.3. But the datasheet also states that this value fulfill the requirements of the same IEC 60034-12.
My customer requires to review the motor selection because of this. The supplier states that the motor is already in accordance with IEC.
I do not have this regulation in my hand and cannot check what it says.
Could someone clarify to me what this regulation actually requires?
thank you very much.
One of the customer requirements is that the figure Is/In (starting current, nominal current) has to be less than 6.5. My customer says that this is required to be in accordance with IEC 60034-12.
My supplier (well-known international motor manufacturer) offered a motor and this value is stated in the data-sheet, the figure is 7.3. But the datasheet also states that this value fulfill the requirements of the same IEC 60034-12.
My customer requires to review the motor selection because of this. The supplier states that the motor is already in accordance with IEC.
I do not have this regulation in my hand and cannot check what it says.
Could someone clarify to me what this regulation actually requires?
thank you very much.





RE: Motor starting current limits - IEC 60034-12
Starting .performance of single-speed three-phase cage induction motors
states only the maximum Slocked/Prated ratio. Indeed,I(locked rotor)=Istarting at the
rated voltage[D.O.L.].
Let's say your motor is 100 kw 400V p.f.=0.9 efficiency=90% Irated=100/sqrt(3)/0.4/0.9/0.9=178.2 A
From Table 2 - Maximum values of locked rotor apparent power for design Nand H
for 63<Pn<630 kW S1=10.
That means Slocked[locked rotor=starting- apparent power] will be 10*100=1000 KVA. Istart=1000/sqrt(3)/0.4=1443.4 A
Istart/Irat=1443.4/178.2=8.1
From this standard, point of view both motors-one with 6.5 and other with 7.3-are suitable since both are less than 8.1.
However, if your customer requires 6.5 maximum he has the right to limit the starting current for his reason-breaker rating, voltage drop at start and other