1.3. Master/Slave Series Operation

Two or more power supplies can be connected in series to obtain a total output voltage greater than that available from one power supply. The total output voltage is the sum of the output voltages of the individual power supplies. Each power supply can be turned on or off separately.

Caution

When connecting power supplies in series, no output terminal may exceed the power supply’s output isolation rating with respect to chassis ground. Refer to the output isolation specification in the power supply’s documentation before configuring a series connection.

Master/slave series operation permits equal voltage sharing under all load conditions and allows complete control of output voltage from one master power supply.

To configure the power supplies for master/slave series operation:

  1. Disconnect power to the power supplies and connect all units and loads in series as shown in Fig. 1.6.

  2. Remove the cover of the UID and set the jumpers according to Fig. 1.3 (UID46) or Fig. 1.4 (UID47, UID53) for the master/slave series configuration. Replace the cover.

  3. Connect a 37-conductor cable from connector JS1 of the master power supply to connector JR2 of the UID.

  4. Connect a second 37-conductor cable from connector JS1 of the slave power supply to connector JR1 of the UID.

  5. Configure the slave power supply for external program (EXT PGM) input. The master unit can be configured for rotary, keypad, external program, or remote input.

_images/diagram_uid_masterslave_series.svg

Fig. 1.6 Master/slave series connection for (a) one or (b) more slave power supplies

1.3.1. Jumper Functions

For all UID models, the master/slave series jumper settings perform the following functions:

  • Jumper connection between JP1 terminals 17 and 18 connects the voltage monitoring voltage, VO2, on the master power supply to the external voltage set point input on the slave power supply. This makes the slave power supply operate at the same voltage output as the master power supply.

  • Jumper connection between JP1 terminals 11 and 12 connects the power output digital control line of the master power supply to the start digital control line of the slave power supply. This connection causes the slave unit to turn on when the master unit is turned on.

  • Jumper connection between JP1 terminals 13 and 14 connects the standby/alarm digital control line of the master power supply to the stop digital control line of the slave power supply. This connection causes the slave unit to turn off when the master unit is turned off or when a diagnostic condition appears.

  • Jumper connections between JP1 terminals 1 and 2; 3 and 4; 5 and 6; 7 and 8; 15 and 16 set the slave current set point to maximum and the voltage trip and over current trip set points just beyond full scale values.

1.3.2. Three or More Power Supplies

Three or more series connected power supplies can be interconnected by applying additional UID units; one UID is required for every slave power supply. As illustrated in Fig. 1.6 for two slave power supplies, follow the previous instructions plus connect an additional 37-conductor cable from JS1 of the second slave power supply to JR1 of the second UID. Connect a 37-conductor cable between connector JR3 and JR2 of the two UID units. Interconnecting UID units routes master control and monitoring signals to all of the slave power supplies.