Pearl 4MWP Series Installation And Operating Instructions Manual
4MWP
4” Submersible Motors
INSTALLATION AND OPERATING INSTRUCTIONS
4MWP
4” Submersible Motors
OVERVIEW
1.
Please read this documentation carefully before installation.
This manual gives important information concerning the installation, use and maintenance of the motors.
The contents of this manual refer to the standard product, as presented in the sales documentation.
The installation and operation must comply with the safety regulations in the country in which the product
is installed.
The entire operation must be carried out in a workmanlike manner.
Failure to comply with the safety regulations not only causes risk to personal safety, it can also damage
the equipment and it will invalidate every right to assistance under guarantee.
2. SAFTEY
Below are the warning symbols used in this manual to warn of perticular dangers
ELECTRIC SHOCK DANGER
The non observance of the prescription involves electric shock risk.
DANGER
The non observance of the prescription involves the risk of damages to persons
and / or equipment.
MECHNICAL DANGER
The non observance of the prescription involves the risk of technical damages
to the motor and / or installation.
3. APPLICATIONS
All the motors in the 4MWP ranges can be used to drive
submersible pumps in the conditions established in
CSA Standard C22.2 No. 100-14 (Motors and Generators)
UL Standard 1004-1 (Electric Motors),
and at the supply voltage / frequency specified on the rating plate.
The shaft extension and flange size of these motors comply with NEMA MG1:2016.
The power of the pumps coupled to these motors must be less than or equal to that of the motors.
4” Submersible Motors
4. LIQUIDS IN WHICH THE MOTOR CAN OPERATE
This motor can be used in cold water.
Do not use this motor with corrosive or explosive liquids
Do not use this motor with particularly dirty or hard water
(impurities may deposit on the outer casing.
5. COMPATIBLE PUMPS
Make sure the motor is compatible with the pump. Incompatible combinations may cause problems.
In particular, before coupling the motor to the pump check that:
- The power of the motor is greater than or equal to the power absorbed by the pump end.
4MWP
- The rpm of the pump matches the rotational frequencey of the motor.
- The pump has a NEMA motor connection and that the shaft turns freely.
6. MOTOR POWERED BY A FREQUENCY CONVERTER
Variable Frequencey Drive’s VFD’s are used to change the rotational speed of the motor so that the out-put of the
attached pump adjusts to the users demand for water.
VFD’s also reduce the starting current and “water hammer” during starting.
PEARL’s three-phase, encapsulated submersible motors can be used with variable frequency drives (VFD) when
used within the guidelines listed here.
All three-phase, encapsulated submersible motors must have the VFD sized based on the motor’s nameplate maximum amps, NOT horsepower. The continuous rated amps of the VFD must be equal to or greater than the motor’s
nameplate maximum amps or warranty will be void.
The VFD must have one RLC output filter to limit the voltage peaks and/or to reduce the dV/dt of the pulses generated by the inverter. The application of the filter will help to reduce the stress on the motor insulation (thermal and
electrical). The filter can be installed at the inverter output to reduce the dV/dt value or at the motor terminals to
attenuate the voltage peaks amplitude.
The motor must reach or pass the 30 Hz operating speed within 1 second of the motor being energized.
If this does not occur, the motor bearings will be damaged and the motor life reduced.
4MWP
4” Submersible Motors
6. VFD continued.
PD WATER SYSTEMS suggests these MAX values for three phase encapsulated submersible motors
Max. Vpeak voltage: 1000 V phase-phase
Max. dV/dt :2000 V/μs
Filters are usually applied when the power cable to the motor is longer than 50ft (15.2m)
PD WATER SYSTEMS suggests the use of an input filter when the VFD is used in a residential area, to protect other
devices connected to the same mains from noise caused by the VFD
Frequency range: 30 Hz – 60 Hz
Drive carrier frequency: The range must be from 4.5k to 5k Hz .
Higher values will increase the quantity of Voltage Spikes x per second and reduce motor insulation lifetime.
Lower values give a poor shape to the power curve.
Ramp-up time / Ramp down time: | df/dt | > 30 Hz/sec (where f indicates the frequency) to ensure the life of the
thrust bearings
The motor’s operating speed must always operate so the minimum cooling flows are reached.
0.50 ft/sec for 6-inch motors
0.98 ft/sec for 4-inch motors
Motor overload protection must trip within a time equal to or faster than how indicated by Class 10 overload curve
and must trip within 115% of the nameplate Max. Amp.
PEARL’s encapsulated submersible motors are not declared inverter duty motors by NEMA MG1
standards. The reason is NEMA MG1 standard part 31 does not include a section covering
encapsulated winding designs.
PEARL’s submersible motors can be used with VFDs without problems or warranty concerns providing
all PD WATER SYSTEMS guidelines are followed.
PEARL’s single-phase, 2- and 3-wire, encapsulated submersible motors hould only be used with the
appropriate variable speed drive.
7. INSTALLATION
Before installing the motor, read both the motor and pump instructions manuals.
Keep both manuals an a safe place.
If the product shows any signs of damage, do not proceed with installation and call your local
stockest / distributor.
You must use suitable equipment and protective devices. Observe all accident prevention regulations.
Installations must always e in accordance with current local and/or national regulations, legislation and bylaws
governing installation of water and power equipment.
PEARL submersible motors are designed to be used in a shaft up vertical position.
During acceleration, the pump thrust increases as its output head increases. In cases where the pump head stays
below its normal operating range during startup and full speed condition, the pump may create upward thrust. This
creates upward thrust on the motor upthrust bearing. This is an acceptable operation for short periods at each start,
but running continuously with upthrust will cause excessive wear on the upthrust bearing.
4MWP
4” Submersible Motors
8. ELECTRICAL CONNECTIONS TO THE ELECTRIC PUMP
Electrical connections may only be performed by a qualified installer in compliance with current
regulations.
Make sure that the supply voltage and frequency are compatible with the electrical panel.
The relative information is shown on the motor rating plate and in the documents supplied with the panel.
Provide suitable short circuit protection on the supply line.
Before proceeding, make sure that all the connections (even if they are potential-free) are voltage-free.
Unless otherwise specified in local bylaws, the supply line must be fitted with:
- a short circuit protection device,
- a high sensitivity ground-fault circuit interrupter (GFCI) residual current circuit breaker (30mA)
for additional protection from electrocution in case of inefficient grounding,
- a general switch with a contact aperture of at least 3 millimetres.
Ground the system in compliance with current regulations
Table 1: Power supply voltage tolerances
Power supply voltage tolerances:-
Frequencey in Hz Phase ~ Voltage Tolerance %
60 1 115v -10% +6 %
60 1 230v -10% +6 %
60 3 480v -10% +6 %
60 3 575v -10% +6 %
Single-phase version
Connect the electric pump to a supply line via a suitable electrical control panel containing the
overload protection and the capacitor.
Refer to the wiring diagram on the outer casing of the motor and in figure 1 and the documentation supplied with
the electrical panel.
Refer to the motor rating plate for the capacity of the capacitor.
Install the electrical panel in a sheltered area.
Three-phase version
Connect the electric pump to a supply line via a suitable electrical control panel .
Install the electrical panel in a sheltered area.
Refer to the documentation supplied with the electrical panel.
For connections to any external control devices (e.g.: pressure switch, float) follow the instructions supplied with
these devices
9. MAINTENANCE, SERVICE
Before proceeding, always make sure the motor is disconnected from the supply line.
Maintenance operations may only be performed by expert and qualified people.
Use suitable equipment and protective devices. Observe all accident prevention regulations.
Do not attempt to disconnect the connector from the motor head cable.
This may only be done by authorised personnel.
The motor does not require any scheduled routine maintenance.
Users wishing to prepare a maintenance schedule should bear in mind that maintenance frequencies depend on the
conditions of use.
For any requirements, please contact our Sales and Service Department.
4MWP
4” Submersible Motors
10. SPARE PARTS
Only use original spare parts to replace faulty components.
Always specify the exact type of motor and code when requesting our Sales and Assistance Service for technical
information or spare parts.
Only use origional spare parts to replace faulty components. Unsuitable spare parts may cause the product to work
incorrectly and cause hazards for people and property.
11. STORAGE
PEARL submersible motors are a water-lubricated design.
The fill solution consists of a mixture of deionized water and Propylene Glycol (a non-toxic antifreeze).
The solution will prevent damage from freezing in temperatures to -23°F (-5°C);
motors should be stored in areas that do not go below this temperature.
There may be an interchange of fill solution with well water during operation. Care must be taken with motors
removed from wells during freezing conditions to prevent damage.
When the storage temperature does not exceed 104°F (40°C), storage time should be limited to two years. Where
temperatures reach 100° to 130°F, storage time should be limited to one year.
Loss of a few drops of liquid will not damage the motor as an excess amount is provided, and the filter check valve
will allow lost liquid to be replaced by filtered well water upon installation. If there is reason to believe there has
been a considerable amount of leakage, consult the factory for checking procedures.
PEARL recommend that you leave the motor in its original packaging until the day of installation.
When standing the motor upright make sure that it cannot fall over (shaft always upwards).
Do not subject the motor to direct sunlight or other heat sources.
12. FREQUENCY OF STARTS
The average number of starts per day over a period of months or years influences the life of a
submersible pumping system.
Excessive cycling affects the life of control components such as pressure switches, starters, relays and capacitors.
Rapid cycling can also cause motor spline damage, bearing damage, and motor
overheating.
All these conditions can lead to reduced motor life.
The pump size, tank size and other controls should be selected to keep the starts per day as low as practical for
longest life.
4 Inch motors should run a minimum of two minutes in order to dissipate heat built up from starting.
Table2: Maximum # starts per day
Motor Rating
Maximum # starts per day
HP KW SINGLE-PHASE THREE-PHASE
0.5 - 1.0 0.37 - 0.75 300 300
1.5 - 5.0 1.1 - 3.7 100 300
7.5 - 10 5.5 - 7.5 50 200
4MWP
4” Submersible Motors
13. MOUNTING POSITION
PEARL submersible motors are designed primarily for operation in the vertical, shaft-up position.
During acceleration, the pump thrust increases as its output head increases. In cases where the pump head stays
below its normal operating range during startup and full speed condition, the pump may create upward thrust. This
creates upward thrust on the motor upthrust bearing. This is an acceptable operation for short periods at each start,
but running continuously with upthrust may cause excessive wear on the upthrust bearing
With certain restrictions, motors are also suitable for operations in positions from shaft-up to shaft-horizontal. As
the mounting position becomes further from vertical and closer to horizontal, the probability of shortened thrust
bearing life increases. For normal thrust bearing life expectancy with motor positions other than shaft-up, follow
these recommendations:
1. All the motors in the range can be installed horizontally as long as the axial thrust of the
pump never falls below 100 N while it is working.
2. Do not use in systems which can run even for short periods at full speed without thrust
toward the motor
3. Minimize the frequency of starts, Six inch motors should have a minimum of 20 minutes
between starts or starting attempts
4” Submersible Motors
14. WATER TEMPERATURE AND FLOW
PEARL standard submersible motors are designed to operate up to maximum service factor
horsepower in water up to 95°F (35°C).
A minimum flow of 0.98 ft/sec for 4” motors is required for proper cooling.
Table 3: Minimum GPM required for motor cooling in water up to 95°F (35°C)
Minimum GPM required for motor cooling in water up to 95°F (35°C)
4MWP
Casing or Sleeve
I.D. Inches (mm)
4" 102 6.5 (24.5)
5" 127 28 (106)
6" 152 55 (208)
7" 178 86 (325)
8" 203 122 (461)
10" 254 209 (791)
12" 305 315 (1192)
14" 356 440 (1665)
16" 406 585 (2214)
The table shows minimum flow rates, in GPM, for various well diameters and motor sizes
15. FLOW INDUCER SLEEVE
If the flow rate is less than specified or coming from above the pump, then a flow inducer sleeve must be used. A flow
sleeve is always required in an open body of water.
Figure shows a typical flow inducer sleeve construction.
Example : A four-inch motor and pump that delivers 60 GPM will be installed in a 8” well.
From Table 2
A 122 GPM flow would be required to maintain proper cooling in an 8” casing, as the 6” casing
requires a min flow of 55gpm then adding an 6” or smaller flow sleeve provides the required cooling.
Worm Worm clamps
4" Motor (1/2-10Hp)
0.98 ft/sec (0.3m/sec)
GPM (l/min)
Saw cuts
Intake
Flow inducer sleeve
Submersible motor
Centering bolt
Centering bolts must
be located on motor
casting. Do not locate
on stator shell
Notch out for cable guard
Lock nuts inside sleeve
Bottom view
Centering bolt hole
(3 required) 120°
4MWP
4” Submersible Motors
16. HOT WATER APPLICATION
When the pump-motor operates in water hotter than 95°F (35°C), a flow rate of at least 11.5 ft/sec is required. When
selecting the motor to drive a pump in over 95°F (35°C) water, the motor horsepower must be de-rated per the
following procedure.
Using next Table to determine pump GPM required for different well or sleeve diameters.
If necessary, add a flow sleeve to obtain at least 11.5 ft/sec flow rate.
Table 4: Minimum GPM required for motor cooling in water above 95°F (35°C)
Minimum GPM required for motor cooling in water above 95°F (35°C)
4" Motor (1/2-10Hp)
Casing or Sleeve
I.D. Inches (mm)
11.5 ft/sec (3.2m/sec)
6" Motor
GPM (l/min)
4" 102 75 (283)
5" 127 330 (1244)
6" 152 650 (2450)
7" 178 86 (325)
8" 203 122 (461)
The table shows minimum flow rates, in GPM, for various well diameters and motor sizes
17. CONTROL BOX MOUNTING
Single phase submersible control boxes feature NEMA 3R enclosures for indoor or outdoor mounting. They should be
mounted in a vertical position as relay manufacturers recommend correct relay
positioning for proper, trouble-free operation.
Control boxes should be shaded from direct sunlight in areas where temperatures exceed 95°F (35°C) as excessive
heat may dry out capacitors and shorten their life. It is advisable to paint the enclosure white if outside in very hot,
sunny climates.
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