TECO-Westinghouse PA7300 Series, Инструкция по установке и эксплуатации

Страница: 71 / 154

(30) PID integral upper bound (Cn-43)
• The upper limit value of value I can be set by Cn-43. To increase the control capability
by integration, increase the value of Cn-43. Reduce the setting of Cn-43 if there is a
risk of load damage or of the motor going unstable from the AC drive’s response when
the load suddenly changes. Set this constant as a percentage of the maximum output
frequency, with the maximum frequency taken as 100%. If the control system vibrates
and vibration cannot be eliminated even by adjusting the integral time (bn-15) or
primary lag time constant (Cn-44), decrease the value of Cn-43. Please note: if the setting of
Cn-43 is reduced too much, the target value and the feedback value will not match. Refer
to page 2-6, the block diagram of PID control section. Also refer to Appendix B.
(31) PID primary delay time constant (Cn-44)
• Constant Cn-44 is the low-pass filter setting for PID control outputs and there is normally
no need to change this setting. If the viscous friction of the mechanical system is high
or if the rigidity is low, causing the mechanical system to oscillate, increase the setting
so that it is higher than the oscillation frequency period. This will decrease the
responsiveness, but it will prevent oscillation. Refer to page 2-6, the block diagram of
PID control section. Also refer to Appendix B.
(32) Energy-savings voltage limit (Cn-45 to Cn-48)
• The upper and lower limits of output voltage are set. If the voltage reference value
calculated in the energy-savings mode exceeds the upper or lower limit value, this upper
or lower limit value is output as voltage reference value.
• The upper limit value is set in order to prevent over excitation at low frequency and the
lower limit value is set in order to prevent stalling at a light load. Limit voltage values
obtained at 6Hz and 60Hz are set: for any limit value other than at 6Hz and 60Hz, the
values are calculated are done by linear interpolation of these values. Settings are made in
% rated voltage.
Please refer to Appendix A for a detailed discussion of Energy-Savings Mode.
2-21
PA 7300 PART II: OPERATION MANUAL
Voltage
Voltage Upper
Limit
frequency
Cn-47
Cn-46
Cn-48
6Hz 60Hz
Cn-45
Voltage
Lower Limit