Allen‑Bradley IntelliVAC ™ 1503VC contactor control module

During operations inside the medium voltage cabinet, it is necessary to comply with the requirements for arc flash and electric shock protection, wear appropriate PPE, perform power-off, electrical testing, grounding, locking, and hanging. There is an energy storage capacitor inside the module, do not touch the circuit board immediately after power failure; When it comes to TDUV external capacitors, the capacitors may retain dangerous voltages and should be discharged and confirmed according to the instructions.

Wiring method and control logic

The top 12 core interface of IntelliVAC is responsible for the main control connection: terminals 1 and 2 are external capacitor negative/positive, used for TDUV or capacitor tripping; Terminals 3 and 4 are the common/output of the mechanical interlocking trip coil; Terminals 5 and 6 are common/output for closed coils; Terminals 7 and 8 are OPEN or JOG command inputs and common terminals; Terminals 9 and 10 are the CLOSE command input and common terminal; Terminals 11 and 12 are auxiliary contact inputs for contactors, usually connected to normally closed auxiliary contacts. At the bottom, there are control power sources L1/L2/N, module status relays 13/14, contactor status relays 15/16, and grounding.

The electric holding contactor can be controlled with two or three wires. In two-wire control, the CLOSE input continuously gives a high level through a holding contact, and instantly disconnecting the input opens the contactor; In three wire control, the START instantaneous closure gives the CLOSE command, the STOP output serves as a self holding contact, and the STOP opens the holding circuit. Regardless of the method, the CLOSE input must maintain a high level to keep the contactor closed. The module limits the closing command of the contactor to every 6 seconds to ensure that the rated number of operations is not exceeded; If the CLOSE command is revoked less than 500 ms after application, the module may malfunction and must be powered off and reset again. It is generally recommended to power on IntelliVAC for at least 4 seconds before issuing the CLOSE command.

Special attention should be paid to the power on safety function: If the module is configured as an electric holding contactor when powered on and the contactor is detected to be closed, the module will not respond to the closing command when Power Up Safety is enabled until the auxiliary contacts return to the correct "open" state and the module is powered off and restarted. If you encounter the problem of 'no matter how hard you press it after power on, it won't close' on site, first check the status of the auxiliary contacts and the power on safety settings, and don't blindly replace the module.

Mechanical interlocking contactors require instantaneous commands: CLOSE and OPEN pulses should be maintained for at least 50 ms. Mechanical interlocking contactors may already be in a closed state when powered on, which is allowed; It is also allowed to give the OPEN command when powering on. If the mechanical locking contactor does not open, first check if the control power supply is below the minimum tripping voltage, and then check if the tripping mechanism is damaged and if the wiring is loose.

Motor Jogging is only applicable to electric holding contactors. When using OPEN input as JOG input, as long as the JOG signal is present, the contactor will close; Signal cancellation opens, bypassing the standard 6-second restart delay for positioning. Note that this is only for jog purposes and cannot replace normal operating logic for a long time.

TDUV is used to keep the contactor from releasing when there is a temporary voltage drop or short-term power loss. When there is no external capacitor, the maximum TDUV of 110/120 V control voltage is about 0.2 s, and 220/240 V is about 1.0 s; longer delays require external capacitors. The triggering conditions include: power supply below 90 V AC/DC after 200 ms of closing request, or power supply below 72 V AC/DC after 200 ms of closing sequence. If the set delay is exceeded and the voltage is still insufficient, the contactor will open and report an undervoltage fault. Capacitor tripping is used for mechanical interlocking contactors: after losing AC, the OPEN command must be given within a few seconds. 120 V/1650 μ F is about 3.5 seconds, 110 V is about 2.7 seconds, 100 V is about 1.7 seconds; 240 V/330 μ F is about 7.5 seconds, 200 V is about 4.7 seconds. The capacitor capacity should not exceed 1650 μ F (120 V) or 330 μ F (240 V), and a current limiting circuit is required for larger capacities, otherwise power on may burn the control fuse.

DIP configuration and power on recognition

The 12 position DIP switch is located at the front edge of the module. Loosen the two screws on the front cover and slide forward to see that position 1 is close to the mini DIN interface. Changing DIP must be powered off, and the new settings will only take effect after being powered on again. The factory default is usually: altitude 0-1000 m, drop out 130 ms, 400 A electrical hold, no TDUV, external capacitor TDUV 0.2 s, Power Up Safety enabled.