Yaskawa SGDB - Manual (Page 164)

APPLICATIONS OF Σ-SERIES PRODUCTS
3.8.5 Using an Absolute Encoder
152
A regenerative resistor reaches approximately 90°C when it is used at 20% of the rated
allowable dissipation value of the resistor. The allowable motor regenerative power (av-
erage) is 180 W for the JUSP-RA04 Type, and 350 W for the JUSP-RA05 Type. If the
regenerative power (average) exceeds the allowable limit value when the servo system
is operating in regenerative operation mode, select an additional regenerative resistor
that has a greater rated allowable dissipation value (W). Therefore, always take the ser-
vo system operation conditions into consideration when determining which regenerative
resistor unit to use.
Example of allowable motor duty conditions
• Motor deceleration torque: Maximum torque
• Load inertia: Five times the motor rotor inertia
Assuming that there is no mechanical loss.
0.2 s 0.2 s 0.2 s 0.2 s
25 s
Motor instantaneous
max. speed
3.8.5 Using an Absolute Encoder
J Outline
An absolute value detection system detects an absolute position of the machine even
when the servo system is OFF. If such a system is to be formed in the host controller, use
an SGMj servomotor with absolute encoder. Consequently, automatic operation can be
performed without zero return operation immediately after the power is turned ON.
SGMj-jjjWj 12-bit absolute encoder
SGMj-jjjSj 15-bit absolute encoder
Always detects
absolute position
Zero return
operation
Absolute encoder
3