NFG250D DC contactor

Features

• Fully sealed structure, with a protection level of IP67.

• Energy-saving coil, reducing coil holding power.

• Fully complies with ROHS requirements.

• Suitable for battery switches, backup power supplies, DC power control, circuit safety protection, etc.

Performance parameters

Coil parameters

Note:

1. The rated electrical endurance of the product is based on resistive load testing, with the maximum inductance of the load not exceeding 300μH; for inductive loads, please consult the factory.

2. The above figure is drawn based on estimates from test and inferred data. It is recommended that users conduct tests and confirm the results based on the actual usage route.

3. When the dielectric withstand voltage and insulation resistance of the product are less than the parameters listed in the product parameter table, the product is defined as having reached the end of its lifespan.

Model Description

①: Product model

②: Contact voltage: (N: Low voltage; G: High voltage)

③: Rated operating current: "250" = 250A

④: A: Equipped with energy-saving circuit board

⑤: B: One  normal close; (None: One normal open)

⑥: C: Magnetic latching

⑦: D: Single coil

⑧: T: Ceramic base

⑨: S: one normal open auxiliary contacts

⑩: Rated voltage of coil: "6" = 6V (DC), "12" = 12V (DC), "24" = 24V (DC), "48" = 48V (DC), "72" = 72V (DC)

⑪: Connection method: (N: External thread; K: Internal thread)

⑫: Installation method: (None: bottom installation)

⑬: Customer Special Code: 01-99

Example: NFG250DS indicates that the rated current of the product load is 250A (resistive), the main contact form is one normal open (external thread) with one normal open auxiliary contacts, the coil voltage is DC 12V, and the bottom installation method is used.

Circuit principle

Outline dimension diagram

Precautions for use

• When installing a relay, always use a washer to prevent the screw from loosening.
  The torque range for tightening screws is specified below. Exceeding the maximum torque value may cause the product to break.
  Main contact terminal force (M8 nut): 8-10N.m
  Torque at the installation point: 1.7 to 3.5 N.m

• The coil of this relay has polarity, so the coil should be connected according to the marking on the product; the contact also has polarity, and the contact should also be connected according to the marking on the product. Variants with energy-saving boards are equipped with a reverse surge absorption circuit, so there is no need to use a surge protector.
• Do not use products that have been dropped.
• Avoid installing the product in a place with a strong magnetic field (near a transformer or magnet) or near objects that emit thermal radiation.
• Electrical life
  This relay is a high-voltage DC switch. In its ultimate breakdown mode, it may lose its proper cutoff function. Therefore, do not use it under conditions that exceed its switching capacity and lifespan parameters (treat this relay as a product with a specified lifespan and replace it when necessary). Once the relay loses its disconnection and cutoff capability, it may cause the surrounding components to burn. Therefore, design the circuit diagram carefully to ensure that the power supply can be cut off within 1 second.

• Diffusion lifetime of internal gas
  This relay utilizes sealed chamber contacts, with the chamber filled with gas. The diffusion lifespan of the gas is determined by the temperature within the contact chamber (i.e., ambient temperature plus the temperature rise generated by the energized contacts). Therefore, it is necessary to ensure that the ambient temperature ranges from -40℃ to +85℃.

• If the coil and contacts of the relay are continuously subjected to rated voltage (or current), and the power supply is cut off and then immediately reconnected, the temperature of the coil increases, and the resistance of the coil increases, resulting in an increase in the product's pull-in voltage, which may exceed the rated pull-in voltage. In this case, the following measures should be taken: such as reducing the load current, limiting the continuous energization time, or using a coil voltage higher than the rated pull-in voltage.
• When dealing with resistive loads, the rated parameters of the main contact specified in the rating are applicable. If inductive loads (L loads) are used and L/R > 1 millisecond, a surge current protection device should be connected in parallel with the inductive load.
• The drive circuit power of the product coil must be greater than the product coil power, otherwise it will reduce the cutting ability of the product.
• Be careful not to let debris and oil stains get on the main outgoing terminal, and the external wiring terminal should make reliable contact with the main outgoing terminal of the product, otherwise it may cause the outgoing terminal to heat up excessively. At the same time, the lead wire connected to the product must have the required conductivity to prevent overheating and affect its lifespan (the cross-sectional area of the lead wire connected to the main contact should be above 150mm2).
• After the product is powered on, the coil will start to switch automatically after about 0.1 seconds. Do not repeatedly turn it off at that position, as doing so may damage the relay.