Cat® Digital Voltage Regulator Caterpillar

Illustration 1	g01425818
Math Model - per unit block diagram for rotating rectifier excitation system.

Vs - Sensing voltage

Vc - Compensated terminal voltage

Vref - Reference voltage

Kg - Programmed gain

Kp - Proportional gain

Ki - Integral gain

Kd - Derivative gain

Td - Derivative time

Vp - Input from the power source for the excitation system

Vrlmt - Forcing limit

Ta - Alternator time limit

Vr - Regulated voltage

Te - Exciter time constant

Ke - Exciter gain

Efd - Exciter field

Illustration 2	g01015474
Typical connections for PMG power input, ABC rotation, and three phase voltage sensing Notes: (A) Contact 52a required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CDVR set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) A three-phase PMG is shown in Illustration 2. For single-phase, remove P6-3 connection. For HV machines using two single phase PMGs in series, connect PMG leads 2 and 3 together, and connect leads 1 and 4 to CDVR pins P6-1 and P6-2, respectively. (H) Sensing potential transformer is required if line voltage exceeds 600 VAC. (I) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 3	g01015488
Typical connections for shunt power input, ABC rotation, and single phase voltage sensing. Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CDVR set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Sensing potential transformer is required if line voltage exceeds 600 VAC. (H) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 4	g01408526
Typical connections for a SE, L-N directly connected power input, ABC rotation, and single phase voltage sensing (generator less than 480 V). Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CDVR set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Sensing potential transformer is required if line voltage exceeds 600 VAC. (H) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 5	g01015546
Typical connections for shunt power input, ABC rotation, and three phase voltage sensing. Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CDVR set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Sensing potential transformer is required if line voltage exceeds 600 VAC. (H) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 6	g01015576
Typical connections for PMG power input, ABC rotation, and single phase voltage sensing. Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CAT Digital Voltage Regulator setpoint. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Three-phase PMG is shown. For single-phase, remove P6-3 connection. For HV machines using two single phase PMGs in series, connect PMG leads 2 and 3 together, and connect leads 1 and 4 to CDVR pins P6-1 and P6-2, respectively. (H) Sensing potential transformer is required if line voltage exceeds 600 VAC. (I) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 7	g01425819
Typical connections for PMG power input, ABC rotation, and single phase voltage sensing. Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CAT Digital Voltage Regulator set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Three-phase PMG is shown. For single-phase, remove P6-3 connection. For HV machines using two single phase PMGs in series, connect PMG leads 2 and 3 together, and connect leads 1 and 4 to CDVR pins P6-1 and P6-2, respectively. (H) Sensing potential transformer is required if line voltage exceeds 600 VAC. (I) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 8	g01112935
Typical connections for internal excitation power input, ABC rotation, and three phase voltage sensing. Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CDVR set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Sensing potential transformer is required if line voltage exceeds 600 VAC. (H) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 9	g01112701
Typical connections for PMG power input, ABC rotation, and single phase voltage sensing (generator less than 600 V). Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CDVR set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Three-phase PMG is shown. For single-phase, remove P6-3 connection. For HV machines using two single phase PMGs in series, connect PMG leads 2 and 3 together, and connect leads 1 and 4 to CDVR pins P6-1 and P6-2, respectively. (H) Sensing potential transformer is required if line voltage exceeds 600 VAC. (I) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 10	g01112717
Typical connections for PMG power input and three phase direct voltage sensing (generator less than 600 V) Notes: (A) 52a contact required only for Var/PF control. Var/PF enabled only when 52a is closed, inactive when open. (B) When excitation disable switch is open, excitation is enabled. (C) When fault reset switch is momentarily closed, any shutdown fault is reset. (D) S1 (SPST, spring return to center-off position) adjusts CDVR set point. (E) Alarm driver and shutdown fault driver are normally off. (F) The ±10 VDC input provides adjustment of output. (G) Three-phase PMG is shown. For single-phase, remove P6-3 connection. (H) Sensing potential transformer is required if line voltage exceeds 600 VAC. For HV machines using two single phase PMGs in series, connect PMG leads 2 and 3 together, and connect leads 1 and 4 to CDVR pins P6-1 and P6-2, respectively. (I) When generator rotation is ACB, the connections for the CTB should be reversed.

Illustration 11	g01429193
Typical connections for cross current compensation

Illustration 12	g01429203
Typical connections for cross current compensation (two CDVR's).

Illustration 13	g01429204
Typical connections for cross current compensation (one CDVR and one DVR).

Illustration 14	g01112822
Typical connections for a manual voltage control