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| Illustration 1 | g00481725 |
Functional Block Diagram Of AC Voltage Display in EMCP II | |
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| Illustration 2 | g00311253 |
Relays In Relay Module (1) Jumper block. | |
| AC Voltage Range Selection | ||||
|---|---|---|---|---|
| GSC P20 Setpoint | External Potential Transformer | AC Transformer Box (ATB) Input Voltage Range | GSC Internal Multiplier | Jumper |
| 700 | None | 0 - 700 | 5 | Required |
| 150 | None | 0 - 150 | 1 | None |
| 300 | 2:1 | 0 - 150 | 2 | None |
| 500 | 3.33:1 | 0 - 150 | 3.33 | None |
| 600 | 4:1 | 0 - 150 | 4 | None |
| 750 | 5:1 | 0 - 150 | 5 | None |
| 3000 | 20:1 | 0 - 150 | 20 | None |
| 4500 | 30:1 | 0 - 150 | 30 | None |
| 5250 | 35:1 | 0 - 150 | 35 | None |
| 9000 | 60:1 | 0 - 150 | 60 | None |
| 15000 | 100:1 | 0 - 150 | 100 | None |
| 18000 | 120:1 | 0 - 150 | 120 | None |
| 30000 | 200:1 | 0 - 150 | 200 | None |
Jumper block (1) is used to select the voltage range of the voltmeter of the GSC. Jumper block (1) is installed for systems with 700 volts full scale AC inputs. Jumper block (1) is NOT installed for systems with 150 volts full scale AC inputs. Also, the jumper block (1) is NOT installed on any unit with external potential transformers. The relay module comes factory equipped with jumper block (1) that is installed.
Jumper block (1) is easily removed by grasping and pulling. It is easily installed by aligning and then pushing the jumper block in. If a jumper block is required but is not available, three separate jumpers can be substituted. Each of the three manufactured jumpers connect a pair of pins. A pair of pins must not touch another pair of pins.
The relay module must be removed from the GSC in order to gain access to the circuit board and jumper block (1). See Testing And Adjusting, "Relay Module - Replace".
The P20 setpoint determines the proper AC voltage range and the internal multiplier that are used by the GSC for calculating AC voltage. The GSC uses the internal multiplier to compensate for the turns ratio of the external potential transformers (if present). The turns ratio of the external potential transformer must match the internal multiplier in order to ensure an accurate AC voltage calculation by the GSC.
The jumper block is located in the relay module. The jumper block connects a "divide-by-five circuit" to the AC voltage input of the GSC. The "divide-by-five circuit" reduces the AC voltage input to a controllable level for the GSC when P20 is 700. When setpoint P20 is 700, a multiplier of five is needed to compensate for the presence of the "divide-by-five circuit". This is done even though no external potential transformer is present.
Note: In order to prevent an inaccurate voltage calculation by the GSC, the jumper block should NOT be installed when P20 is programmed to a value that is different from 700. The other values (150 through 30 000) are used with an external potential transformer. The values result in input voltages from 0 to 150 ACV at the AC Transformer Box (ATB). No further reduction of the input voltage is required.