Eaton MET User Manual

8. Program the control as required for the new system
voltage:
a. Set FC 41 to for the system configuration (Wye, Delta
Leading, Delta Lagging).
b. Set FC 43 to the desired Load Volts.
c. Set FC 44 to the Overall Pot. Ratio as shown on the
nameplate for the corresponding Load Volts or as
determined for voltages other than shown on the
nameplate.
d. Set FC 44 to the Internal PT Ratio as shown on
the nameplate for the corresponding Load Volts or
as determined for voltages other than shown on the
nameplate.
9. Complete any other programming as required. Refer to
Table3 and Table4 for guidance on typical settings.
Allowable system voltages and calculation of overall
PT ratio
If the system voltage is other than those listed on the
nameplate, it can be determined if there is sufficient ratio
correction available from the control winding (internal PT)
taps and the Ratio Correction Transformer (RCT) taps to
allow the CL-7 control and motor to function properly. The
general guideline is that the overall PT ratio is sufficient if
the voltage delivered to the control for the nominal voltage
conditions is in the range of 115 –125 V.
To determine the voltage delivered to the control, use the
following procedure:
1. Calculate the desired PT ratio.
Desired PT Ratio = Desired system voltage ÷ 120 V
2. Choose the internal PT ratio on the nameplate closest
to the desired PT Ratio.
3. Calculate the actual voltage at the output of the internal
P T.
Internal PT Output Voltage = Desired system voltage ÷
Selected Internal PT Ratio
4. Choose the RCT tap (133, 127, 120, 115, 110, 104)
closest to the internal PT output voltage.
5. Given the RCT input tap, use Table5 to determine the
RCT ratio.
6. Calculate the control input voltage.
Control Input Voltage = Internal PT Output Voltage ÷
(RCTRatio)
7. Calculate the overall PT ratio.
Overall PT Ratio = Internal PT Ratio x (RCT Ratio)
EXAMPLE: If a 60 Hz, 7620 V regulator is to be used on a
system with a nominal voltage of 2500 V, the following is
determined:
1. 2500 V ÷ 120 V = 20.8
2. Choose 20:1 for the internal PT ratio.
3. Internal PT output voltage = 2500 V ÷ 20 = 125 V
4. Best RCT input tap is 127.
5. RCT ratio is 1.058.
6. Control input V = 125 ÷ 1.058 = 118 V
This is within allowable range.
7. Overall PT ratio = 20 x 1.058 = 21.2:1
Table5. RCT ratios
RCT Input Tap RCT Ratio
133 1.108
127 1.058
120 1.000
115 0.958
110 0.917
104 0.867
22
INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN225003EN April 2018
CL-7 Voltage Regulator Control

Eaton MET Specifications

General

Brand	Eaton
Model	MET
Category	Cables and connectors
Language	English