Wholesale Discount Floating Ground Resistor - Crowbar/Chopper Resistor – Wepower

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Wholesale Discount Floating Ground Resistor - Crowbar/Chopper Resistor – Wepower Detail:

█ Application

Crowbar resistor is mainly used in low voltage ride through technology of wind power inverter. It is used at the rotor side of wind turbine generator to bypass the rotor side converter. In case of low voltage disturbance in the power grid, the DC bus voltage and rotor current shall be prevented from being too high. It mainly works in fault state to damp stator flux linkage. Crowbar resistors can dissipate huge amounts of energy instantaneously.

It is mainly used in the frequency conversion / converter system of doubly fed variable speed constant frequency generator units to improve the low voltage ride through capability of generator units, which is limited by the power grid
Large current impact caused by voltage drop protects excitation converter and limits rotor winding over voltage.

█ Feature：

The resistance material is imported alloy steel, which can absorb large energy impact in a short time, and can meet different power requirements.

█ structures：

Mica sandwich structure, traditional metal carrier grid structure and block carrier structure:
1. mica sandwich structure, with small volume, low cost and large heat capacity, is suitable for absorbing large energy in a short time and for single impact at long intervals (once a week).
2. with the traditional metal grid structure, the product has relatively moderate volume, relatively moderate cost and good heat dissipation performance. It is suitable for multiple impacts in a short time (once every 30 minutes). It can be used in crowbar resistor, chopper resistor and braking resistor circuits.
3. block carrier structure, the product has strong impact resistance and good heat dissipation performance. High structural strength and moderate price. Suitable for short-time multiple impact. It can be applied to crowbar resistor, chopper resistor, braking resistor and other circuits.

█ Life Time of Crowbar Resistor

200J	1 times/second
220KJ	1 times/30mins	35000 times（20 years of life）
640KJ	1 times/week	1000 times（20 years of life）
1360KJ	1 times/month	260 times（20 years of life）
Take 1.5MW windmill generator as an example, environment temperature ≤ 60℃

█ Resistor Material Comparison

Material	（g/mm3）	（Ω·mm2/m）	J/(g·K)	W/(m·K)	ppm/℃
SUS304	7.9	0.72	0.5	13.2	≤1400
SUS316	7.93	0.78	0.45	13.23	≤900
SUS310S	7.98	0.88	0.46	13.2	≤600
Cr20Ni80	8.4	1.09	0.441	16	≤100

█ Selection Table

Energy	Resistance	Time	Dimension（mm）
Energy	Resistance	Time	（L）mm	(W)mm	(H)mm
50KJ	3R	30mS	420	160	95
200KJ	2R	3.8S	285	178	150
500KJ	3.3R	3.8S	670	150	150
1.0MJ	0.36R	0.1S	395	190	153
1.5MJ	0.45R	3S	520	292	100
2.0MJ	0.4R	30mS	868	175	130
2.0MJ	0.5R	30mS	943	195	135
2.2MJ	0.7R	1S	446	240	153
2.5MJ	0.95R	3S	597	400	200
3.0MJ	0.7R	1S	432	240	153