19
MicroStar B
Service manual
MicroStar B
rev06
09
09
09
09
09
The transformer's nominal power is calculated based upon the sum of power from the
single motors driven:
Where: Pn Motor =
Power absorbed motor
in (W)
N
= Max. speed of motor in RPM.
Cn
= Nominal torque of motor in (Nm).
Pn Motor = N * Cn / 9,55
P(VA)=Pn1+Pn2+..
Power transformer
1.13 Power supply
VDC = Vdc motor / 0,85
Example: Brushless motor with the following data:
In =5 (A)
Ri = 1 (Ohm)
E=48 (V) at nominal speed 3000 (RPM)
Vdc motor = E+(Ri * In)
E = Ke * N° / 1000
Voltage motor
Where the Vdc motor is a sum of FCEM + the drop R*I for the winding resistance motor
The FCEM of the motor "E", may be calculated by the formula:
Vdc motor = 48 + ( 1 * 5) = 53V
VDC = 53 / 0,85 = 62,3V
62,3V is the VDC voltage request for the power supply. You'll use a transformer with the
secondary V2 = 62 / 1,41= 44Vac
When you use the transformer with V2= 44/48Vac, it is correct.
Note: In multi-axis applications, the transformer's power can be downgraded by 30%.
If the max. power transformer calculated is 6KVA contact the factory.
If the secondary voltage of power supply is VDC, the Vdc motor is calculated by the formu-
la:
Misure unit:
E = Ke *n°/1000 (Vdc)
Im = I motor (A)
Ri = Winding resistance (Ohm)
Ke =Voltage constant (V/kRPM)
n° = MAX speed (RPM)
