Carrier 5H - Manual (Page 15)

5H80 COMPRESSOR
II-POUND SPRING, R-22 8 R-502
T ~
L
_j
.------------------------------------------------------------------ ^
r -
-T f—
3 8 PSI
z
Ui
— — •
4 4 PSI
STEP NO. 2 1
REDUCTION ~i--------
STEP N0. V i
U
<o
a.
N
ui
u.
Li.
5 5
STEP N0. 3
PSI '
J
J U
<
74 PSI
------------------------------------------------- .-------------------- - - U
H
STEP NO 4 U=UNL0AD1NG POINT
% OF FULL DISPLACEMENT
NO OF ACTIVE CYLINDERS
25
2
371/2
3
621/2
5
87'/2
7
100
8
5HI20 COMPRESSOR
II-POUND SPRING, R-22 8 R-502
L= LOADING POINT L
L
P----------------------
L
r—"*^1
L
-------------- *—
—
CAR '*'* PSI
P
z
Ui
6 75 PSI
5 2 PSI
STEP N0.1 i
U
(/)
C L Ui
u.
u.
88 PSI -- U
_l
- - U
________ !!
1-
f______________________________________
U= UNLOADING POINT
U
7o OF FULL DISPLACEMENT 33'/3 50 66^/3 83'/3 100
NO OF ACTIVE CYLINDERS 4 6 8 10 12
Fig. 10 - Operating Sequence of Capacity Reduction Steps with 5F,H Type Compressors (Contd)
(Using the Standard 11-Pound Range Adjustment Spring)
Electrical Compensation of Compressor Capacity
Control “ Electrically actuated capacity control is
available for all 5F,H compressors, exclusive of
the 5F20 and 5F30. Tight location of this unit may
make it impossible to install this control in the
field and thus it should be installed prior to final
placement on location.
This point at which the compressor starts to
unload is set by the external adjustment stem.
This method of external capacity control utilizes
a modulating type electric damper motor with
gears to connect this motor to the adjusting stem.
Either
Honeywell or Barber-Colman motors are
available. The Honeywell motor is suitable for use
with all Series 90 controllers. The B-G motor
is suitable for use with all TP dr EYEX^ Series
controllers.
Operation of the motor may be controlled by
either a temperature or pressure sensing device
which reacts to changes in the conditions being
controlled. If the control signal is such that less
compressor capacity is needed, the modulating
S U P E R S E D E S
SECTION
5F,H-1X
PAGES 1-42
DATE 11-63
motor rotates the capacity control stem clockwise
and thus raises the control point at which the com­
pressor starts
to unload. The opposite movement
of the stem occurs when more compressor capac­
ity is needed. Figure 11 shows a typical electric
compensation arrangement.
The modulating motor and gear train provides
two full turns of the capacity control stem. These
two turns will move the unloading point thru a
range of 16 psi for R-12 and R-500and 22 psi for
R-22 and R-502.
Pneumatic Compensation of Compressor Capacity
Control - Adding a control air line to the external
pneumatic control connection permits pneumatic
resetting of the control point in accordance with
changes
in operating conditions. Each pound of
change in the air pressure resets the control one
pound in the same direction. Thus, a one-pound
rise in air pressure will cause unloading to begin
at a suction pressure one pound higher than the
original control point, etc. Figure 12 shows atyp­
ical pneumatic control arrangement.
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PAGE
DATE 5F,H-1XA
15
10-66