Quantech QTC2015T, Руководство пользователя, Страница: 56 / 72

QUANTECH
FORM QTC2-eg1 (515)
56
Circuit Breaker Calculations
max dual Elem fuse max CB (moP)
= 2.25 x Current of largest motor + ∑ (remaining FLAs or RLAs)
for this name plate the formula below was used:
= 2.25 * r r r Qty* r 0.49 + flA
Pump
This formula will calculate the ACTUAl moP but a table is referenced to provide the ap-
propriate moP. Using an approximate match, look up the value of the calculated ACTUAl
moP in Column A. find the largest value i.e. less than or equal to the value in Column A.
once found, the value in Column C which shares the same row is the valued USEd in the
system. e.g. e.g. Using the same example that was used to calculate the mCA, calculate
the moP:
Answer: ACTUAl = 2.25*20.4 + 20.4 + 0 + 2*2.6 + 5.29 = 45.9 + 30.89 = 76.79Com-
paring against values in Column A: 70 < 76.79 < 80, therefore the USEd moP found in
Column C is 70.
ACTUAL
COLUMN
A
MINIMUM
COLUMN
B*
MAXIMUM
COLUMN
C
0 15 0
15 20 15
20 25 20
25 30 25
30 35 30
35 40 35
40 45 40
45 50 45
50 60 50
60 70 60
70 80 70
80 90 80
90 100 90
100 110 100
110 125 110
125 150 125
150 175 150
175 200 175
200 225 200
225 250 225
250 300 250
300 350 300
350 400 350
*Note: Column B is used if one were calculating
the minimum dual Elem fuse which is not relevant
to this exercise.