Application – Three-Phase Motors

Inline Booster Pump Systems (continued)

9.Controls-Soft Starters and VFDs: Reduced voltage starters and variable speed drives (inverter drives) may be used with Franklin three-phase submersible motors to reduce starting current, upthrust, and mechanical stress during start-up. The guidelines for their use with submersible motors are different than with normal air cooled motor applications. Refer to the Franklin Electric Application, Installation and Maintenance (AIM) Manual Reduced Voltage Starters section or Variable Speed Submersible Pump Operation, Inverter Drives sections for specifi c details including required fi ltering.

10.Motor Overload Protection: Submersible motors require properly sized ambient compensated Class 10 quick-trip overloads per Franklin’s AIM Manual guidelines to protect the motor. Class 20 or higher overloads are NOT acceptable. Franklin’s SubMonitor is strongly recommended for all large submersibles since it is capable of sensing motor heat without any additional wiring to the motor. Applications using Soft Starters with a SubMonitor require a start-up bypass - consult the factory for details. SubMonitor can not be used in applications using a VFD control.

11.Motor Surge Protection: Properly sized, grounded and dedicated motor surge arrestors must be installed in the supply line of the booster module as close to the motor as possible. This is required on all systems including those using soft-starters and variable speed drives (inverter drives).

12.Wiring: Franklin’s lead assemblies are only sized for submerged operation in water to the motor nameplate maximum ambient temperature and may overheat and cause failure or serious injury if operated in air. Any wiring not submerged must meet applicable national and local wiring codes and

Franklin Cable Chart tables 16-21. (Notice: wire size, wire rating and insulation temperature rating must be known when determining its suitability to operate in air or conduit. Typically, for a given size and rating, as the insulation temperature rating increases its ability to operate in air or conduit also increases.)

13.Check Valves: Spring-loaded check valves must be used on start-up to minimize motor upthrusting, water hammer, or in multiple booster (parallel) applications to prevent reverse fl ow.

14.Pressure Relief Valves: A pressure relief valve is required and must be selected to ensure that, as the pump approaches shut-off, it never reaches the point that the motor will not have adequate cooling fl ow past it.

15.System Purge (Can Flooding): An air bleeder valve must be installed on the booster sleeve so that fl ooding may be accomplished prior to booster start- up. Once fl ooding is complete, the booster should be started and brought up to operating pressure as quickly as possible to minimize the duration of an upthrust condition. At no time should air be allowed to gather in the booster sleeve because this will prevent proper cooling of the motor and permanently damage it.

16.System Flush – Must Not Spin Pump: Applications may utilize a low fl ow fl ushing operation. Flow through the booster sleeve must not spin the pump impellers and the motor shaft. If spinning takes place, the bearing system will be permanently damaged and the motor life shortened. Consult the booster pump manufacturer for maximum fl ow rate through the pump when the motor is not energized.

Table 37 Franklin Cable chart (See 12. Wiring)

CABLE

MOTOR NAME-

TEMP.

PLATE RATED

RATING

AMPS FULL

(°C)

LOAD

75

3-LEAD (DOL)

6-LEAD (Y-∆)

 

90

3-LEAD (DOL)

6-LEAD (Y-∆)

 

 

3-LEAD (DOL)

135

6-LEAD (Y-∆)

 

#10 AWG

 

#8 AWG

#6 AWG

#4 AWG

#2 AWG

IN AIR

IN

IN AIR

IN

IN AIR

IN

IN AIR

IN

IN AIR

IN

CONDUIT

CONDUIT

CONDUIT

CONDUIT

CONDUIT

 

 

 

 

 

 

40A

28A

56A

 

40A

76A

52A

100A

68A

136A

92A

69A

48A

97A

 

69A

132A

90A

173A

118A

236A

19A

 

 

 

 

 

 

 

 

 

 

 

44A

32A

64A

 

44A

84A

60A

112A

76A

152A

104A

76A

55A

111A

 

76A

145A

104A

194A

132A

263A

180A

 

 

 

 

 

 

 

 

 

 

 

63A

46A

74A

 

51A

104A

74A

145A

98A

185A

126A

109A

80A

127A

 

88A

180A

129A

251A

320A

320A

219A

 

 

 

 

 

 

 

 

 

 

 

SOURCE OF CABLE

AMPACITY

US N.E.C., 2002 edition, tables 310.16 & 310.17

US N.E.C., 2002 edition, tables 310.16 & 310.17

Standard AAR (American

Association of Railroads)

RP-585

Based on 30 °C maximum ambient with cable length of 100 feet or less.

37

Page 46
Image 46
Franklin 2007 manual Franklin Cable chart See 12. Wiring, Air, Source of Cable Ampacity