Generally connected between ground and neutral of transformers, ners. Er600vc is designed for use on systems up to 600 v for indoor applications. Neutral grounding resistors may come equipped with accessories such as ground fault sensing devices. The big large value resistor to ground has two purposes. Neutral grounding resistors catalogs directindustry. Place the neutral grounding resistor on the prepared base. Asco neutral grounding resistors schneider electric documents. Pdf grounding the neutral of electrical systems through. Technical information 69 cox avenue erlanger, ky 41018 usa phone.
The method of neutral point connection in threephase systems determines the power frequency voltage increase on nondefective phases in case of a ground. Limiting the possible current that can flow in such an event not only reduces damage to equipment but also helps safeguard personnel in the vicinity. Inherently committed to electrical safety, igard is providing its customers with ground fault and arc flash solutions to protect their people, their equipment and ultimately, their business. Neutral grounding resistor systems can be inserted between the neutral and ground in a power system to provide ground fault protection through resistance. A widely utilised approach to managing fault currents is the installation of neutral earthing resistors ners. In both types of grounding, the resistor is connected between the neutral of the transformer secondary and the earth ground, as shown in figure 5. Available in optional moistureproof enclosure shown on left for outdoor applications. The majority of systems limit the fault current to 200400 amps in the usa, based on the guidelines contained in ieee142 when a fault occurs, the neutral grounding resistor ngr limits the current that can flow from ground back to the transformer. The main purpose of a neutral grounding resistor ngr is to limit the fault current present in a single line to ground fault. Er5kv for use on systems up to 4160 v for indoor applications.
If a sensing resistor is present both neutral and ground terminals come prewired by the factory. Consult ms resistancess entire neutral grounding resistors catalogue on directindustry. Install the cable entrance bushing in the hole provided, and tighten securely if applicable. This limits the fault current on grounds throughout the entire system. The neutral point is grounded with a resistor which restricts the ground fault current to a. Vishay milwaukee resistor offers a complete line of custom and standard neutral grounding resistors ngrs, also known as neutral earthing resistors ners.
If applicable please follow the instructions below when connecting this type of equipment. Optimal neutral ground resistor rating of the medium. Grounding the neutral of electrical systems through lowresistance grounding resistors. In a resistancegrounded system, the neutral of the transformer or generator is connected to ground through a resistor. Ners, sometimes called neutral grounding resistors, are used in an ac distribution. The fundamental purpose of a neutral grounding resistor ngr is to limit ground fault currents to safe levels so that all the electrical equipment in a power system is protected. Pdf it seems common knowledge that threephase shortcircuit currents are the worst. Lowresistance neutral point grounding is selected for extended systems. Igard igard ground fault protection, power resistors. This can cause high ground fault current typically 10,000 to. Pdf grounding the neutral of electrical systems through low. Without the resistor, the tube grid would pick up charge and gradually bias the tube into conduction. Ngr reliable neutral grounding resistors, high current.
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