5. POWER SUPPLY
Select a transformer according to the load condition and the model of the
motor for which the transformer is used. Each transformer has secondary
winding taps for three amplifiers so that it can be connected to two or three
For a machine with typical operating conditions, select a transformer
according to the following guideline.
(Sum of 3–phase power requirements of all motors) 0.6 y transformer rating
Table 5.2.1 Table 5.3.1
When two or more motors are used, the transformer rating
obtained using the above expression may be less than the
actual power requirements of any one of those motors.
Should this occur, use the motors’ maximum power
requirements as the transformer rating.
(Example) The power requirements of the α22/2000 and
α40/2000 (with fan) are indicated in Table 5.2.1, as shown
α22/2000 : 5.9 kVA
α40/2000 (with fan) : 11.3 kVA
Using the expression given above, the transformer rating is
calculated as follows:
(5.9 + 11.3)*0.6 = 10.32 kVA
The power requirement of the α40/2000 (with fan) is 11.3
kVA, this being greater than the calculated transformer
rating of 10.32 kVA. So, the transformer rating should be
How to Select a