Cranes Relays

Low Voltage Monitoring Relays

Low Voltage Monitoring Relays (LVMR) are designed specifically to address power loss during hoist lowering operations.

Hinged to provide easy access for repairs and inspections, their arc chutes and magnetic blowout structures are designed to quickly absorb and dissipate the heat caused by arcing. The pivot pin assembly provides positive pin locking so that the bearing pin remains stationary with respect to the operating movement of the forged armature. A leaf spring attached to the unit base and the arc chute holds the chute in the “down” or functioning position.

The LVMR continuously monitors bus voltage and de-energises the UV relay if the bus voltage falls below a value that will safely operate contactors and relays.

The LVMR distinguishes the difference between main power and regeneration power produced by a motor. It constantly monitors the DC bus voltage and sets the series brake automatically when it detects a power loss condition. When the voltage drops below the point where relays or contactors can reliably pick up and seal (as defined by the current NEMA standards), the hoist control panel will shut down and set the brake.

Heavy-Duty Mill DC Replays

Designed for heavy industry service and are suitable for use on moving machinery. They are arranged for steel panel mounting with front connections.

Unit circuit blocks have two captive mounting screws and are interchangeable between relays. They are easily convertible from normally open to normally closed or vice versa. Contacts are of double break design.

Magnetic Overload

These overload relays are designed for use on DC power circuits to monitor motor loading.

Inverse time limit trip relays are normally set to trip between 125% and 175% of full load motor current. Instantaneous trip type overload relays use a dry type dashpot and are normally set to trip between 200% and 300% of full load motor current.

Field Control DC Replays

This family of motor field control relays consists of a relay with 1NO pole and a relay with 1NC pole.

The opening and closing of the contact changes based on the amount of current going through the coil. The relays are equipped with one or two coils, depending on the application. When the relays leave the factory, they are adjusted for average load conditions.

Heavy-Duty Mill DC Relays - Type KC

The Type KC line of control relays complements the mill-type, front-connected DC contactors (Bulletin 7400, Type K). Each device is completely assembled and ready for mounting on metal panels without additional insulators or special hardware.

These DC Mill type relays are designed for heavy industry service and are suitable for use on moving machinery. They are arranged for steel panel mounting with front connections. Unit circuit blocks have two captive mounting screws and are interchangeable between relays. They are easily converted from normally open to normally closed or vice versa. Visible contacts are of double break design.

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