Page 12 - Fuse link Catalogue

MOTOR CIRCUIT PROTECTION

Table 1 Full Load Currents of Typical 3-Phase
Induction Motors at Voltages Shown
Motor Rating
All type ‘T’ fuse links have excellent ability to protect motor circuits.
kW HP 220V 380V 415V 440V 550V 660V
When selected in the manner shown below, they not only withstand
0.37 0.5 2.0 1.15 1.05 1.0 0.8 0.7
motor starting surges and full load currents without deteriorating, but
0.55 0.75 2.7 1.6 1.5 1.4 1.1 0.9
also provide superior short circuit protection to associated motor
0.75 1 3.9 2.3 2.0 1.9 1.5 1.3
starter components. Leading manufacturers of motor starters can offer
1.1 1.5 4.7 2.8 2.5 2.4 1.9 1.6
ASTA certified type ‘c’ co-ordination to Appendix C of BS4941:1979
1.5 2 6.5 3.8 3.5 3.3 2.6 2.2
(IEC292-1) and more recently type 2 co-ordination to IEC 947-4-1, by
2.2 3 9.3 5.4 5.0 4.7 3.8 3.2
using 660V type ‘T’ fuse links in combination with their chosen
3 4 12 7.1 6.5 6.1 4.9 4.1
contactors and overload relays.
4 5.5 15.4 9.0 8.4 7.9 6.4 5.3
Please consult IPD Industrial Products for further information on this
5.5 7.5 20.7 11.9 11 10.3 8.2 6.9
subject.
7.5 10 28 16.1 14.4 14 11.2 9.3
11 15 39.1 23 21 19.8 15.8 13.2
15 20 52.8 30.5 28 26.4 21.1 17.6
18.5 25 66 38 35 33 26.4 22
22 30 77 45 41 39 31 26
30 40 103 60 55 52 42 35
Selecting HRC Fuse Links to Protect 3-Phase Motor Circuits 37 50 128 75 69 65 52 43.3
1. Table 1 opposite gives motor full load currents at various voltages. 45 60 151 87 80 75 60 50
In the absence of specific information obtain the motor FLC from this 55 75 185 107 98 92 74 62
table. 75 100 257 148 136 128 102 85
2. The motors are assumed to produce the starting conditions shown 90 120 308 180 164 154 123 102
on Table 2. 110 150 370 214 196 185 148 123
3. Choose the recommended fuse link for the motor FLC and starting 132 175 426 247 226 213 170 142
condition from Table 3 (D.O.L. starting) or Table 4 (assisted starting). 150 200 500 292 268 252 202 168
4. For certified type C and type 2 co-ordinated motor starters, 550 & 160 215 - 300 275 260 207 173
660V fuse links must be specified. 200 270 - 391 358 338 270 225

240 320 - 467 428 404 323 269
280 375 - 533 488 460 368 307
300 400 - 573 525 495 396 330
320 425 - 587 538 507 406 338

Table 2 Assumed Starting Conditions
Motor rating Direct-on-line starting conditions Assisted start conditions
Up to 1kW 5xFLC for 5 secs 2.5xFLC for 20 secs
1.1 to 7.5kW 6xFLC for 10 secs
7.6 to 75kW 7xFLC for 10 secs 3.5xFLC for 20 secs
Greater than 75kW 6xFLC for 15 secs

IPD INDUSTRIAL PRODUCTS Phone: 1300 556 601 www.ipdgroup.com.au
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