LET
Specifications
Description: BS 88 style stud-mount high speed semiconductor fuses.
Dimensions: See dimensions illustrations.

Ratings:
Volts: 240Vac/150Vdc
Amps: 25-180A
IR: 200kA RMS Sym.
Agency Information: CE, Designed and tested to: BS 88 Part 4, IEC 269 Part 4, UL Recognized. All fuses above have been tested at 318Vac. Consult Cooper Bussmann for specific UL Recognition status.

Electrical Characteristics
Total Clearing I2t

The total clearing I2t at rated voltage and at power factor of 15% are given in the electrical characteristics. For other voltages, the clearing I2t is found by multiplying by correction factor, K, given as a function of applied working voltage, Eg, (rms).

Dimensions (mm)


Arc Voltage

This curve gives the peak arc voltage, UL, which may appear across the fuse during its operation as a function of the applied working voltage, Eg, (rms) at a power factor
of 15%.

Power Losses

Watts loss at rated current is given in the electrical characteristics. The curve allows the calculation of the power losses at load currents lower than the rated current. The correction factor, Kp, is given as a function of the RMS load current, Ib, in % of the rated current.

Catalog Numbers

Catalog Numbers	Type	Rated Current RMS-Amps	I2t(A2 Sec)			Watts Loss
			Pre-arc	Clearing
				at 120V	at 240V
25LET	LET	25	18	120	250	4
32LET		32	32	200	450	5
35LET		35	50	320	600	5
50LET		50	100	500	1400	7
63LET		63	180	1100	2200	9
80LET		80	300	1900	3800	10
100LET		100	600	3800	7500	10
125LET		125	600	3800	7500	16
160LET		160	1100	7000	16000	20
180LETa		180	1600	1200	29000	21

• Watts loss provided at rated current.
• Note: 7LET, 10LET, 12LET and 16LET are available for replacement purposes on existing equipment.

Features and Benefits
• Excellent cycling capability
• Excellent DC performance
• Low arc voltage and low energy let-through (I2t)

Typical Applications
• DC common bus
• AC and DC drives
• Power converters/rectifiers
• Reduced voltage starters

Time-Current Curve


Peak Let-Through Curve