© 2012 Harmonic Inc.
52
Electra 1000, Version 3.0, Rev M
Appendix E
Wiring the –48 VDC Power Supply
If your encoder has the optional –48 VDC power supply, follow these steps to wire the power
supply. Figure E-1 shows the DC power supply, which is located on the back panel.
Figure E-1: DC power supply
E.1 Getting Started
Before you begin wiring the –48 VDC power supply, make sure that you provide the
necessary overcurrent protection, wires, and power connector.
E.2 Power Source Specifications
The DC power source feeding the encoder must meet the following requirements:
Electrically isolated from any AC power source.
Positive ground. The Positive bus of the DC power source must be reliably connected to
the Ground bus.
Each feed-pair must provide a continuous supply of power that meets the specifications
shown in Table E-1.
E.3 Overcurrent Protection
To provide overcurrent protection:
Provide overcurrent protection devices as part of each rack housing encoders.
Locate a readily accessible disconnect device between the DC power source and the
encoder.
Use a 10-amp double-pole fast trip, DC-rated disconnect device for each DC power
connector.
NOTE:
Overcurrent protection devices must meet applicable national and local electrical safety codes
and be approved for the intended application.
Table E-1: DC Power Source Requirements
Parameter
Specification
Voltage
40 to 60 VDC
Max operating current
8 amps
Max input surge current
20 amps
