Motor and pulley data, Blower speed adjustment – Energy Tech Laboratories DSH User Manual
Page 14
JOHNSON CONTROLS
14
FORM 145.32-IOM1 (908)
MOTOR AND PULLEY DATA
EVAPORATOR - STANDARD BLOWER MOTOR AND DRIVE DATA
Belts
HP
Frame Eff.(%) Pitch Dia.(in)
Browning #
Pitch Dia.(in)
Browning#
Rating / Size
Qty
2 TON
845-1170
1/4
56
66.0
2.6-3.6
1VP40 X 5/8
5.4
AK56H
4L370
1
3 TON
675-1010
1/3
56
75.0
2.0-3.0
1VP34 X 5/8
5.2
AK54H
4L370
1
4 TON
675-1010
3/4
56
75.0
2.0-3.0
1VP34 X 5/8
5.2
AK54H
4L400
1
5 TON
745-1120
1
143
75.0
2.0-3.0
1VP34 X 7/8
4.7
AK49H
4L390
1
CONDENSER - STANDARD BLOWER MOTOR AND DRIVE DATA
Belts
HP
Frame Eff.(%) Pitch Dia.(in)
Browning #
Pitch Dia.(in)
Browning#
Rating / Size
Qty
2 TON
770-1070
1/2
56
75.0
2.6-3.6
1VP40 X 5/8
5.9
AK61H
4L500
1
3 TON
745-1071
3/4
56
82.5
2.0-3.0
1VP34 X 5/8
4.7
AK49H
4L390
1
4 TON
615-920
1
143
82.5
2.0-3.0
1VP34 X 7/8
5.7
AK59H
4L490
1
5 TON
770-1070
1.5
145
84.0
2.6-3.6
1VP40 X 7/8
5.9
AK61H
4L500
1
Model
Motor
Adjustable
Motor Pulley
Model
Drive Range
(RPM)
Fixed
Blower Pulley
Drive Range
(RPM)
Motor
Adjustable
Motor Pulley
Fixed
Blower Pulley
BLOWER SPEED ADJUSTMENT
The RPM of the supply air and condenser air blow-
ers will depend on the required CFM, and the static
resistance of both the supply/discharge and the return/
intake duct systems. With this information, the RPM
for the blowers can be determined from the blower
performance tables. Adjustment of blower speed is
accomplished as follows:
1. Loosen belt tension by moving motor towards the
blower shaft via the adjustable mounting base.
2. Loosen the setscrew in the adjustable motor pul-
ley flange. Remove external key on pulleys 4-in.
dia and larger.
3. Blower speed will increase when moveable flange is
adjusted towards the fixed flange (closed). Blower
speed will decrease when the moveable flange
is adjusted away from the fixed flange (opened).
Pulleys are adjustable only in half-turn increments.
Do not open pulley more than five full turns for “4L”
and “A” belts, or six full turns for “B” belts.
4. Once the pulley has been opened/closed the ap-
propriate number of turns, replace the external key
and tighten the adjustment set screw. Proper torque
is 110 - 130 in-lbs.
5. Install drive belt and adjust motor mount to tension
belt.