User Manual Of EL7-EC** AC Servo
24
Selection of regenerative resistor
Table 2-3 Recommended selection of regenerative resistor
Model no.
Internal
resistance (Ω)
Internal resistor
power rating (W)
Minimum
resistance (Ω)
Minimum power
rating (W)
EL7-EC400N
100
50
50
50
EL7-EC750N
50
75
40
50
EL7
-EC1000N
50
100
30
100
Calculation of regenerative resistance under normal operation
Steps:
1. Determine if driver comes with a regenerative resistor. If not, please prepare a
regenerative resistor with resistance value higher than might be required.
2. Monitor the load rate of the regenerative resistor using front panel (d14). Set the
driver on high velocity back and forth motions with high acceleration/deceleration.
3.Please make sure to obtain the value under following conditions: Driver temperature <
60
℃
, d14<80(Won’t trigger alarm), Regenerative resistor is not fuming, No overvoltage
alarm(Err120).
Pb(Regenerative power rating) = Resistor power rating x Regenerative load rate (%)
Please choose a regenerative resistor with power rating Pr about 2-4 times the value of
Pb in considered of harsh working conditions and some ‘headroom’.
If the calculated Pr value is less than internal resistor power rating, external resistor is
not required.
R(Max. required regenerative resistance) = (380
2
– 370
2
)/Pr
Problem diagnostics related to regenerative resistor:
If driver temperature is high, reduce regenerative energy power rating or use an
external regenerative resistor.
If regenerative resistor is fuming, reduce regenerative energy power rating or use
an external regenerative resistor with higher power rating.
If d14 is overly large or increasing too fast, reduce regenerative energy power rating
or use an external regenerative resistor with higher power rating.
If driver overvoltage alarm (Er120) occurs, please use an external regenerative
resistor with lower resistance or connect another resistor in parallel.
Please take following precautions before installing an external regenerative resistor.
1. Please set the correct resistance value in Pr0.16 and resistor power rating Pr0.17 for
the external regenerative resistor.
2. Please ensure the resistance value is higher or equals to the recommended values in