Comparisons In Torque Vs. Rotation Speed And Stator Coil Temperature Rise - Hitachi G 10SD2 Technical Data And Service Manual

6-2. Comparisons in Torque vs. Rotation Speed and Stator Coil Temperature Rise

Fig. 1 and Fig. 2 show comparisons of the rotation speed and the stator coil temperature rise between some
competitive models with respect to torque. Torque represents the magnitude of load, i.e., the amount of pressing
force, cutting depth and forward force in actual cutting jobs. This shows that a powerful motor is less likely to burn
out because it has both a minimum drop of rotation speed even with a higher torque and a lower stator coil
temperature rise at the same torque.
12,000
10,000
8,000
6,000
4,000
2,000
0
Fig. 1 Comparison in torque vs. rotation speed and stator coil temperature rise (G 10SD2 and G 12S2)
Fig. 1 indicates:
(1) The Models G 10SD2 and G 12S2 are equipped with high-power motors and improved cooling mechanisms,
and are superior to the Models G 10SD1, G 12S1, B and C in the rotation speed and the stator coil
temperature rise at the same torque.
(2) The motor speed of the Models G 10SD2 and G 12S2 is about 10 % higher than that of B and C at the same
torque. This means that the working efficiency of the Models G 10SD2 and G 12S2 is superior to the other
maker's models.
(3) The stator coil temperature rise of the Models G 10SD2 and G 12S2 is lower than that of B and C at the same
torque, and the torque when the motor is burnt out is about 1.3 times higher compared to B and C. This
means that the overload durability of the Models G 10SD2 and G 12S2 is superior to the other maker's
models.
Rotation speed of spindle
G 10SD2
HITACHI
G 12S2
HITACHI
B
G 10SD1
HITACHI G 12S1
G 10SD1
G 12S1
C
HITACHI
B
C
Load
--- 7 ---
G 10SD2
G 12S2
Stator coil temp.rise
: Burn-out point
400
200
0