Motor Cooling; Head Loss In Casing; Starting Frequency - Pentair Pentek Series Electronic Manual

SECTION 6: Pentek
6.7 Overload Protection
Submersible motors must have Class 10 overload protection that will disconnect the power within 10 seconds in the
case of a locked rotor. To accomplish this, fixed-heater overloads are used. Refer to Section 10 for appropriate heaters.
The chart is based upon total line amps. Divide the motor amps by 1.732 when using a 6-lead motor with a Y-Delta
Starter. Notice: General Electric overload heaters are only usable with general electric overload relays. Do not adjust
relays to exceed nameplate amps.

6.8 Motor Cooling

Pentek 6" motors are designed for minimum water flow of 0.5 ft. /sec. past the motor. Maximum water temperature is
95° F (35° C).
6" MOTORS: MINIMUM COOLING WATER FLOW
I.D of casing
6
7
8
10
12
14
16
If the flow is less than specified, a flow-inducer sleeve can be installed. This will act like a smaller casing size, and
force flow around the motor to aid cooling. Always use a flow-inducer sleeve when the pump is in open water.

6.9 Head Loss In Casing

Use the chart below to account for the head loss around the pump.
Head loss in feet for flow past motor
6" Motors
100
150
200
250
gPM
300
400
500
600

6.10 Starting Frequency

To extend the life of the pump motor and control, limit the number of starts
to 100 per 24 hours. If higher starting frequencies are necessary, consult
your factory. To prevent overheating, run motor for a minimum of two
minutes. For starting frequency, refer to section 5.10.
32
6" Submersible Motors
®
Flow (GPM) required
9
25
40
85
140
200
280
cAsiNg iNside diAMeter
6" 7"
1.7
3.7
6.3 0.5
9.6 0.8
13.6 1.2
23.7 2.0
3.1
4.4
8"
0.2
0.4
0.7
1.0