High-voltage current limiting fuse for motor protection - XI'AN XIANGYUAN ZHEN-LI ELECTRIC CO.LTD.

This product applies to the indoor AC 50 ~ 60Hz system with the rated voltage of 3.6~12kV, and may be used along with other protective devices (such as the switch, vacuum contactor, etc）. as short-circuit and overload protection element for the high-voltage motor and other power equipment.

Model

International model XRNM3A- (3.6～12)/□ -50

Equivalent model

电动机保护用高压限流熔断器

BS standard:

电动机保护用高压限流熔断器

Basic parameters as per DIN standard

Product Model	Equivalent Model	Rated Voltage (kV)	Rated Current of Fuse Element (A)	Standard Size		Rated Breaking Current (kA)
Product Model	Equivalent Model	Rated Voltage (kV)	Rated Current of Fuse Element (A)	φA(mm)	L(mm)	Rated Breaking Current (kA)
XRNM3A-7.2	WDLDJ	7.2	25, 31.5, 40, 50, 63	φ51	292	50
	WELDJ		63, 80, 100	φ66
	WFLDJ		125, 160	φ76
	WXLDJ		160, 200, 224, 250, 315	φ88
	WFMDJ		25, 31.5, 40, 50, 63, 80, 100, 125, 160	φ76	442
	WKMDJ		200, 224, 250, 315	φ76	442
XRNM3A-12	WDLDJ	12	20, 25, 31.5, 40, 50	φ51	292	50
	WELDJ		50, 63, 80	φ66
	WFLDJ		80, 100, 125	φ76
	WXLDJ		160, 200	φ88
	WFMDJ		25, 31.5, 40, 50, 63, 80, 100	φ76	442
	WKMDJ		125, 160	φ76
	WXMDJ		200, 224	φ88

Outline dimensions as per DIN standard

电动机保护用高压限流熔断器

Fig. 1 Outline drawing of XRNM3A fuse link

Basic parameters as per BS standard

(1) Bus fuse

Model	Equivalent model	Rated Voltage (kV)	Rated Current of Fuse Link (A)	Main Dimensions (mm)				Rated Breaking Current (kA)
				A	B	C	D
XRNM3A-3.6	WDF.0	3.6	50, 63, 80, 100, 125	377	254	305	Φ51	50
	WFF.0		125, 160, 200				Φ76
	WKF.0		250, 315, 355, 400
XRNM3A-7.2	WFF.0	7.2	25, 31.5, 40, 50, 63, 80, 100, 125, 160	486	403	454	Φ76	50
	WKN.0		200, 224, 250, 315, 355
XRNM3A-12	WKX.0	12	25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, 224	683	600	650	Φ76	50

Note: The above-mentioned are the rated parameters of single tube, and higher rated current value may be obtained through the parallel connection of fixed structure.

Outline drawing of bus fuse

电动机保护用高压限流熔断器

a) Single fuse

电动机保护用高压限流熔断器

b) Double-parallel fuse

电动机保护用高压限流熔断器

c) Triple-paralel fuse

Fig. 2 Outline and installing dimensions of bus fuse

Basic outline parameters of plug-in fuse

in mm

Size code Model	A	B	C	D	E	F	G
WDF*0	390	312	80	140	246	254	φ51
WEF*0							φ76
WKF*0
WFN*0	500	461	150	160	266	403
WKN*0
WFX*0	690	659	350	160	268	600

Outline drawing of plug-in fuse

电动机保护用高压限流熔断器

Fig.3

Main technical data:
The fuse under specified operating conditions is able to reliably break any fault current from the minimum breaking current (1.6～3) ln to the rated breaking current 50kA.
Time - current characteristic curve is as shown in Fig. 4, Fig. 5 and Fig. 6.
Current limiting characteristic curve is as shown in Fig. 7.

Fig. 4 XRNM3A-3.6 time - current characteristic curve
Fig. 5 XRNM3A-7.2 time - current characteristic curve
Fig. 6 XRNM3A-12 time - current characteristic curve

Fig. 7 XRNM3A current limiting characteristic curve

Rational use of fuse
The rated current of the fuse for direct start shall be selected according to the following formula
Iy=NInδ
Where,
In- full load current of motor
δ- Coefficient of colligation as shown in the following table
N- Ratio of starting current to full load current, generally N = 6
Iy-Current value during start-up
Starting Frequency n/h
2
4
8
16
δ
1.7
1.9
2.1
2.3
The point corresponding to ly value at the starting shall be plotted on the time - current characteristic curve, and the curve corresponding to the point or the curve on the right side of point means the fuse’s curve. The rated current of fuse shall be greater than 1.3 times the full load current of motor.
XRNM

Starting Frequency n/h	2	4	8	16
δ	1.7	1.9	2.1	2.3