Allen Bradley IntelliVAC 1503VC Series E Control Module

The operation inside the medium voltage cabinet must comply with the requirements of arc flash and electric shock protection, wear appropriate PPE, perform power-off, electrical testing, grounding, locking, and hanging. There is dangerous voltage inside the module, do not open the cover 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.

Interface terminals and control methods

The top 12 core interface 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. The electric holding contactor uses a 5/6 drive to close the coil, while the mechanical locking contactor uses a 3/4 drive to trip the coil and a 5/6 drive to close the coil.

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 the contactor opens when it is instantly disconnected; 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 are restored to the correct 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. Only disable the power on safety function when necessary, otherwise it may cause unsafe working conditions.

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 (400 A about 70 V AC, 800 A about 80 V AC), and then check if the OPEN command has been reached, 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. The operation is limited to starting twice every 12 seconds and cannot replace normal running logic for a long time.

Special attention should be paid to emergency stop applications: if it is necessary to cut off the control power to achieve emergency stop, contacts should be connected in series in the L1 control power circuit. If the TDUV function is used, the contactor will not immediately open and will have to wait for the TDUV delay to expire. Therefore, TDUV is not suitable for emergency stop situations that require immediate power-off.

Boundary between TDUV and capacitor tripping

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 the 110/120 V control voltage is about 0.2 s (400 A and 800 A are the same), and 220/240 V is about 1.0 s. A longer delay requires an external capacitor, and DIP can be set to 0.2, 0.5, 1.0, 2.0 s. The triggering conditions include: the power supply is below 90 V AC/DC within 200 ms after the closing command, or below 72 V AC/DC after 200 ms of closing sequence (electrical hold). If the undervoltage persists beyond the set delay, the contactor will open and report an undervoltage fault or warning.

Capacitor tripping is used for mechanical interlocking contactors: the OPEN command must be given within a few seconds after AC loss. At 120 V and 1650 μ F, it takes about 3.5 seconds (actual 120 V), at 110 V it takes about 2.7 seconds, and at 100 V it takes about 1.7 seconds; at 240 V and 330 μ F it takes about 7.5 seconds, and at 200 V it takes about 4.7 seconds. Beyond this time, the contactor cannot be tripped by IntelliVAC and can only be released by pressing the release button on the contactor door. The capacitance should not exceed 1650 μ F (120 V) or 330 μ F (240 V), and larger capacities are not recommended. Minimum withstand voltage of capacitors: For 120V applications, at least 200V DC (recommended 250V DC) should be used, and for 240V applications, at least 400V DC (recommended 450V DC) should be used.