6850000D
Copyright © Liberty Pumps, Inc. 2021 All rights reserved.
5 | EN
Pump Design
XLSG/XLSGX-Series grinder pumps are designed for continuous
underwater operation. The motor and pump form a close coupled,
watertight unit. The induction motor is insulated against heat and
moisture in accordance with Class F 311°F (155°C) regulations.
The motor is protected against damage from water entry by two
mechanical seals. The lower seal is 2-piece, silicon carbide/silicon
carbide and the upper seal is unitized graphite impregnated
silicon carbide.
The impeller and volute are designed for efficient flow
characteristics and clog-free operation. The hardened cutters
grind solids and fibrous matter into small particles that can be
safely pumped through small diameter piping.
Pump System Components
Control Panel
Float switches must be connected to an intrinsically safe
circuit in the control panel as per the requirements of
Chapter 5 of the National Electric Code®.
XLSG/XLSGX-Series grinder pumps require a separate, approved
control panel for automatic operation. Operation will be
according to the control selected. Refer to separate
manufacturer’s instructions supplied with the unit.
The control panel shall be installed outside the hazardous area
and appropriately isolated and sealed to prevent any potential
ignition or explosion. Only approved controls that have
intrinsically safe float switch connections shall be used. Mounting,
installation and wiring connections are specific to the control
panel used. Refer to the manufacturer’s instructions supplied with
the unit.
IMPORTANT:
When connecting an XLSG/XLSGX-Series pump to
an existing control panel, verify the panel is correctly sized and
equipped for the pump.
The control panel for 3-phase pumps shall have provisions for the
thermostats that open the motor contactors in order to maintain
the T4 (135°C) temperature class. Do not exceed voltage/current
combinations for the thermostat: 16 VDC/20 Amps, 115 VAC/
22 Amps, 277 VAC/8 Amps, 600 VAC/4 Amps. All models have a
temperature (T) class rating of T4 with thermostats connected.
Failure to use the proper circuitry and to connect the thermostat
will void the T4 temperature class of the pump and will drop the
temperature class to T3 (200°C).
Intrinsically safe control panels designed for use with the XLSG/
XLSGX-Series pumps available from Liberty Pumps can be found
at http://www.LibertyPumps.com/Portals/0/Files/
panel_selection_guide.pdf or contact Liberty Pumps.
1-phase pumps require a panel-mounted start circuit consisting of
a start capacitor, run capacitor, and start relay, which are available
separately. Refer to Table 1 for these control panel components.
Overload Protection
XLSG/XLSGX-Series grinder pumps require overload protection in
the control panel. The motor control unit shall be approved and
shall be properly sized or adjusted for the full load input power
indicated on the pump nameplate. It is important to properly
adjust or select the motor control overload protection. The full
load amps on the nameplate should be used as a baseline, but it is
important to consider that events such as supply voltage variation
or large solids passing through the pump can temporarily increase
current draw. To avoid possible nuisance tripping, it may be
necessary to adjust overloads to a value slightly higher than the
full load input power indicated on the pump nameplate.
Thermostats
XLSG/XLSGX-Series grinder pumps are protected from
overheating by means of thermal switches (thermostat) located in
the motors. For 1-phase models, a hermetically sealed thermal
overload device is mounted on the motor windings and wired
directly in series with the motor’s winding, interrupting power in a
high heat condition. 3-phase models utilize two thermostats
mounted in series directly on the motor windings. The thermostat
circuit shall be connected to a control panel that will stop power
to the pump in a high temperature condition.
Both 1- and 3-phase pumps are constructed with class F materials,
with a maximum operation temperature of 155°C.
Failure to use
the proper circuitry and connection of the thermostat will drop
temperature class from T4 to T3 on 3-phase units
.
Many panels have a manual reset button for the thermostats on
3-phase units. This button must be pressed to reset the system
after the pump has cooled. 1-phase units reset automatically after
the pump has cooled.
RISK OF SERIOUS INJURY OR DEATH
Table 1. Control Panel Components 1-Phase
Required Component and Specification
Liberty Pumps
P/N
208 V 1-phase Start Kit
(contains 3 items listed separately below)
K001640
Start Capacitor, 270–324 µF 220/250 VAC
Run Capacitor, 65 µF 370 VAC
Start Relay
230 V 1-phase Start Kit
(contains 3 items listed separately below)
K001641
Start Capacitor, 270–324 µF 220/250 VAC
Run Capacitor, 50 µF 370 VAC
Start Relay
