UFC 3-535-01
17 November 2005
Figure 15-4. Sample Calculation of CCR Test Data
(1 of 2)
SAMPLE CALCULATIONS, CCR TESTING
DATA:CCR: 30KW, 480V input, 5-step (2.8A - 6.6A)
Cable: #8 AWG, 5kV, L-824 Type C, 20,000 feet primary circuit
Circuit Load:70 Edge lights @ 120W (100W transformer)
16 Thld/end lights @ 200W (200W transformer)
10 signs @ 100VA (at step 5)
5 signs @ 200VA (at step 5)
(at the input to the isolation transformer)
3 signs @ 300VA (at step 5)
1 REIL system (2 units) @ 400W, connected by power adapter, with Power Factor
of 0.43. [Note that in this example the REIL is adjusted only for PF. Some REIL
may require further adjustment, based on manufacturer's information.]
Cable losses (resistance) @25C: 0.68Ω/1000'
Fixture losses (obtain from Mfg - This example assumes 18 percent for 120W,
and 11 percent for 200W lights)
CALCULATIONS:
1.CCR rated output voltage, VRMS = 30KW/6.6A = 4,545V
2.Total connected load, KVA = { Wlamps + [WREIL]/1000 + [VAsigns]/1000
PF
+ Fixture losses/1000 + Cable losses/1000 }
Fixture losses = (70 x 120 x 0.18) + (16 x 200 x 0.11) = 1,864W
Cable losses = I2R = [6.6] 2 x (0.68 x 20) = 592W
TOTAL KVA = (70x120) + (16x200) + (400/0.43) + (10x100 + 5x200 + 3x300) + 592 + 1,864
1,000
= 17.89 KVA
where:
KVA = kilovolt-amperesVRMS = Rated output voltage of CCR
V = volts Wlamps = Wattage of light fixtures
A = amperes WREIL = Wattage of REIL
KW = kilowatts PF = Power Factor
CCR = Constant Current RegulatorI = Current, in amperes
R = Resistance in Ohms, Ω
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