Spencer Vacuum Cleaning Systems - Manual (Page 3)

All tubing should be of ample size to minimize frictional loss. It
is absolutely essential that all joints be airtight and that there be
no leaks in the system. Leaky air pipes consume a surprising
amount of power and impair the operating efficiency of the
system.
A rubber connecting sleeve is supplied with most machines. It
should be installed so that it covers a gap of approximately one
inch as illustrated. The mounting clamps should be tightened to
effect an airtight connection.
It is important that the tubing or piping not touch or butt
the Vacuum Producer; there must be a gap between the
machine and piping or tubing.
Electrical
Caution: Be sure motor, starter, controls and other electrical
equipment is the proper type suitable for the application
and environment and complies with all applicable codes.
Be sure that the motor furnished with this machine is rated for
the same type of voltage available at the installation site. In
making the electrical connections, follow the wiring instructions
furnished. Wire and fuses should be of ample capacity to insure
that proper voltage is maintained at the motor terminals while
starting and running. It is important that proper starting equip-
ment be used. All AC machines should be equipped with a
magnetic contactor or a manual or automatic compensator
depending on the machine size and the installation regulations
of the local power company. The starters should have thermal
overload protection as well as true low-voltage protection.
Start-Up
Coupling-Equipped Machines
Caution: Before start-up, the coupling must be aligned in
accordance with the information contained in Section II,
Coupling Alignment, or with the manufacturer’s instruc-
tions accompanying each coupling.
The following procedures apply to start-up of all Spencer
Vacuum Producers.
Caution: The Vacuum Producer must be electrically wired
with regard to the correct direction of rotation. A direction-
of-rotation arrow is affixed to the casing. To check rotation
direction depress start button, immediately depress stop
button and observe that the motor drive shaft rotation
coincides with the arrow attached to the casing. Available
discharge positions (viewed from intake end) and the
correct relationship of the discharge position to rotation
are shown in the following diagram.
Under no circumstances should the Vacuum Producer be
operated without being connected to the tube system with
which it is used or motor overload will occur.
When starting up a Vacuum Producer it is recommended
that a blast gate or other control device be closed. When
first starting the Vacuum Producer, an ammeter should be
connected to the motor circuit and the control device opened
until full load current is reached. At this point, the blast gate
locking nut should be tightened. This prevents motor overload.
The blast gate may then be used for throttling purposes.
Current readings at motor must be compared with readings
on ammeters (when furnished) to be sure they are the same.
If readings are not the same, contact Spencer’s Service
Department.
Periodic Operation
Caution: All Vacuum Producers should be operated period-
ically. This can be accomplished through bi-weekly alternate
operation of the machine(s).
Parallel Operation
Caution: Check valves must be installed on the inlet of
each Vacuum Producer connected in parallel to prevent air
flow back through the unit not in operation. When operating
two or more Vacuum Producers in parallel it is necessary
to be sure that each machine carries its respective share of
the load.
After accomplishing start-up of each machine, proceed as follows.
Check the current reading at each motor to be sure they are the
same. If current readings are approximately the same it indicates
Vacuum Producers are sharing equal system load. It may be
necessary to re-adjust the control device to attain similar readings
on the ammeters.
In most cases low flow protection for the equipment is
required.
Caution: Operation of Positive Displacement Vacuum
Producers in parallel with Centrifugal Vacuum Producers is
not recommended and may result in damage to the
Centrifugal Vacuum Producer.
Surge (Unstable Low Flow)
Caution: Do not operate the Vacuum Producer below the
minimum safe operating flow. Operation below the mini-
mum flow will result in surge or in excessive discharge
temperatures. Damage to the Vacuum Producer because of
operating below minimum safe flow will not be covered by
Spencer warranty.
A unit in surge can produce a breathing or pulsating dis-
charge noise. It may also be detected by movement on an
ammeter scale or manometer. Increasing the volume flow
sufficiently should eliminate this condition. This may be
accomplished by bleeding air into the Vacuum Producer.
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