Magic Aire HHA Series, Инструкция по установке, эксплуатации и обслуживанию

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035-000029-001 Page 39 HHA IOM 1.4 10/11/2021
SERVICE
General
1. Place a suitable walkway to protect floor insula-
tion whenever entering the fan section.
2. Review Safety Considerations at beginning of
these instructions. Good safety habits are im-
portant tools when performing service proce-
dures.
3. To make speed measurements, use a laser-style
tachometer or use VFD output.
Fan Motor Replacement
NOTE : After reassembly of the motor/wheel assem-
bly, the entire assembly must be dynamically re-
balanced in accordance with International Standard
ISO 1940-1.
WARNING : Failure to rebalance motor/wheel assem-
bly in step 9 could result in dangerous operating con-
ditions and will void the unit warranty. Shut off motor
power and lock out power supply.
Procedure:
1.
Disconnect and tag power wires at motor termi-
nals.
2. Remove fan motor and wheel assembly from
mounting plate (Figure 15).
3. Remove motor/wheel assembly from the AHU
(Figure 16).
4. See Figure 17 and 18. Loosen all set-screws.
Depending on the size of the bushing, unscrew
one or two set-screws completely, oil them and
screw them into the removal holes (Figure 18
item 4). Pull on one or both set-screws, until the
bushing (item 1) comes free of the hub (item
2).
5. Remove the impeller.
6. Install impeller on new motor (or new impeller
on motor): Clean all bare surfaces (locating
surfaces of bushings and motor shaft) and
degrease them.
7. Push the bushing (Figure 18 item 1) into the
hub (item 2) and make the holes coincide as
shown in Figure 18. Use witness marks as a
guide. Oil set-screws lightly and screw in
(item 3) - do not tighten yet.
8. Push the impeller with bushing (item 1) onto
the shaft without loading it (using a hoist if the
impeller weight requires it), align the axial
position and tighten the set-screws (item 3)
symmetrically. For HHA sizes 04 through 25,
tighten set screws to 14.5 ft-lb. Fill empty
holes with grease, to prevent the penetration
of foreign bodies.
DANGER
NEVER enter an enclosed fan cabinet or reach
into a unit while the fan is running.
LOCK OPEN AND TAG the fan motor power dis-
connect switch before working on a fan. Take fus-
es with you and note removal on tag. Electric
shock can cause personal injury or death.
LOCK OPEN AND TAG the electric heat coil pow-
er disconnect switch before working on or near
heaters.
Failure to follow these warnings could lead to per-
sonal injury or death.
DANGER
Failure to torque impeller set screws properly may
lead to impeller failure and high velocity debris
that is a lethal hazard!
Failure to rebalance wheel/motor after re-
assembly could result in unacceptable vibration,
possibly leading to impeller failure—lethal hazard!
Failure to follow these warnings could lead to per-
sonal injury or death.
Figure 18
MOUNTING
PLATE
MOTOR
MOUNTING
BOLTS
Figure 19
Figure 20