20
Table 16 Capacity Control Reduction Steps
*Two controlled cylinders (to 331/3%) available on request for 5F30.
Principle of Operation of the System — An increase in suc-tion gas pressure, which requires increased compressorcapacity, causes the needle valve to close. Therefore, lubrica-tion oil pressure in power element increases. Increased oilpressure in power element moves the power piston upward andthe suction valve discs are allowed to seat.Table 17 indicates control oil pressure at which controlledcylinders start to and completely unload.Different points of control pressure on 5F30 are obtained byusing springs with different loading rates in the power element.
COMPR
MODEL
CONTR
CYL
CAP. STEPS (% Full Load Cap.)
100 871/2831/375 662/3621/250 371/2331/325
% Full Load Bhp
10090868074 716050 4538
Number of Active Cylinders
5F20 12————1——
5F30* 13——2—————
5F40 34——3——2——1
5F60 465432
5H40 34——3——2——1
5H46 34——3——2——1
5H60 465432
5H66 465432
5H80 687——— 532
5H86 687——— 532
5H120 81210 864
5H126 81210 864
0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
U
U
L
U
U
U
U
UNIT
SIZE
REDUCTION
STEPS
1
2
3
4
1
2
3
4
3
1
2
3
1
2
3
1
2
5F40
5H40
5H46
5F60
5H60
5H66
5H80
5H86
4
1
2
3
4
U
U
U
U
U
U
U
U
U
U
5H120
5H126
PSI DIFFERENTIAL
R-22 & 502, R507/404A; 11-LB RANGE ADJUSTMENT SPRING
L - LOAD
U - UNLOAD
U
L
L
L
L
U
U
U
U
U
R-12, R-134a; 7-LB RANGE ADJUSTMENT SPRING
Fig. 5 Operating Sequence of Capacity Reduction StepsFig. 6 Capacity Control 5F20, 5F30