MINGRUI offers high resistance grounding equipment for wye connected generators. Our equipment is normally designed to limit the line-to-ground fault current to blow 15amp for generators rated up to 14,400 volts. These units will provide a high resistance neutral during a fault condition, while allowing the system to operate as an ungrounded system during normal operating conditions. The configuration basically consists of a dry-type single phase transformer with a resistor connected across the secondary. The primary of the transformer is then connected between the wye point of the generator and ground.

MINGRUI generator grounding equipment is normally supplied with the transformer and resistor installed in a common enclosure. Continuous rated units are usually compartmentalized to separate the resistor assembly from the transformer which is subject to overheating. Units do not normally include any relaying or control circuitry, but do offer the transformer secondary wired to a terminal block installed in an external junction box.

Basic construction

Transformer:For continuous time ratings, the transformer must be capable of withstanding rated current for an indefinite period of time; therefore, the KVA rating of the grounding transformer is equal to the rated line to neutral voltage times the desired neutral current. For a short time rating, the KVA rating of a grounding transformer will be smaller because the unit is designed to carry its rated current for a limited time.

Resistor Assembly:The resistance value is calculated by dividing the secondary voltage by the rated current necessary to obtain the desired fault current on the primary. Resistor elements are selected to best meet the current and voltage requirements of the system. A typical assembly includes all stainless steel elements, bus bars and terminals.

Safety enclosure: Safety enclosure: our resistor assemblies are available with grounded safety enclosures to protect personnel and wildlife from harm. Screened and louvered enclosures are available in a variety of finishes including painted, power coated, mill galvanized, hot-dipped galvanized, aluminum and stainless steel.

Options: A number of additional options are available including entrance bushings, current transformers, elevating stands, and disconnect switches.