Rockwell Automation 1391ES AC Servo Controller - Manual (Page 59)

Transformers and Shunt Regulators
Chapter 9
9-57
Shunt Regulator Operation Refer to Chapter 4 for an explanation of the shunt regulator circuitry. The
nominal data for the shunt regulator is as follows:.
Overvoltage Trip Point = 405V DC
±
2.5%
DC Bus Shunt “ON” Point = 386.4V DC
DC Bus Shunt “OFF” Point = 366.9V DC
Nominal DC Bus Voltage
= 300V DC
DC Bus Undervoltage Detect = 145V DC
±
20%
The shunt regulator behavior is modified by an adjustable duty cycle timer.
The timer is used to model the shunt resistor temperature. A selector switch
(SW1) determines the temperature level and therefore the average power
level at which the controller will fault. When this level is reached, the
controller will be forced to fault on an overvoltage. This action would be
equivalent to turning the shunt regulator off.
The Duty Cycle Selector Switch is located on top of the controller near
terminal Block, TB5 (see Figure 1.1). The switch has 16 positions
designated “0 to F,” with “0” being the lowest value and “F” the highest.
The higher the setting, the higher the average power seen by the shunt
resistor. The Duty Cycle Selector Switch settings for various
controller/shunt combinations are shown in Tables 9.A and B.
Important: Accurate operation of the Duty Cycle Timer is dependent on
the shunt resistor value. Do Not substitute alternate values.
Table 9.A provides the required Duty Cycle Selector Switch settings and
resistor power trip points for factory supplied configurations. An optional
external resistor assembly (catalog number 1391-MOD-SR22A) is
available for the 22.5A 1391B-ES.
Table 9.A
Maximum Switch Settings and Trip Points for Factory Supplied Configurations
* Denotes SW1 setting at time of shipment. User must reconfigure controller when using optional
1391-MOD-SR22A.
Configuration
1391B-ESAA15 w/ standard 16 ohm internal resistor
1391B-ESAA22 w/ standard 12 ohm internal resistor
1391B-ESAA22 w/ 9 ohm external resistor
(1391-MOD-SR22A)
1391B-ESAA45 w/ standard 5 ohm external resistor
SW1
Switch
Setting
B*
B*
F
D*
Nominal
Trip Point
164w,
±
10%
162w,
±
10%
386w,
±
10%
715w,
±
10%
ATTENTION: The designated settings for the factory supplied
configurations must be used or damage to the controller may
result.
!