JVL MAC050 - Page 95

JVL A/S - User Manual - Integrated Servo Motors MAC050 - 4500 91
3.2 Power Supply
3.2.5 Estimating the peak current from the supply.
The peak current drawn from the DC power supply is dependant on the following pa-
rameters:
-Maximum motor speed.
- Maximum load torque.
- Supply voltage used.
The calculation is done as follows:
Conditions (example)
Maximum speed = 2500 RPM = 262 Radians/sec.
Maximum torque= 0.9 Nm (peak torque) @ MAC140 is used with 300% (full torque)
Supply voltage = 24VDC nominal
Worst case efficiency of the MAC50-141 motors = 0.8 (80%)
Power calculation:
Power = (speed x torque)/efficiency = (262 x 0.9)/0.8 = 295W
Current calculation:
Current at peak torque = power / supply voltage = 295/24 = 12.3Amp.
Please note that the peak current is only at maximum during for example an acceleration
or deceleration. The peak current can be reduced if the “Torque” setting is lowered. The
peak current will decrease proportionally with the Torque setting.
Example: Half torque = half peak current.
The below curve shows how the power and current are behaving as a function of the
motor speed during acceleration, constant speed and deceleration.
Only MAC050 to 141
Speed
(RPM)
Supply
Current
(A)
Supply
Power
(W)
Time
4000
3000
+15
-15
+300
-300
2000
+10
-10
+200
-200
1000
+5
-5
+100
-100
0
TT1276-02GB
Lower current and power since only
friction exist at constant speed
Current and power rises to max
during acceleration. The inertia in
the system need to get up in speed.
When decreasing speed - power (energy)
will be returned to the supply and cause
a negative current flowing in the supply line.
0
0
Average supply power