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XJS 50

Sulzer submersible sludge pump XJS 50

The submersible sludge pump XJS 50 is ideal for pumping sludge and water mixed with solids. Pumps with built in AquaTronic unit will always have correct direction of impeller rotation, ensuring peak performance and reduced wear. 50 Hz: head max 28 meters, flow max 25 l/s. 60 Hz: head max 31 meters (102 feet), flow max 26 l/s (413 gpm).


Electric submersible pump.
Maximum submergence: 20 m. Protection class IP 68.
Max temperature of pumped medium at max power input and continuous duty 40 ºC.
Max medium density 1100 kg/m3. pH of the pumped medium 5-8. Free passage: 48 x 60 mm.
Max number of starts 30/hour.Min impeller diameter for duty with low water level or intermittent dry running.
Max impeller diameter requires half motor or more submersed for continuous duty. (Pump can operate lying down.)

Electric motor

3-phase squirrel-cage induction motor, 50 Hz:

Service factor 1.1. Class F insulation.
Motor rating P2: 5.6 kW. 2 pol.
Speed: 2930 rpm.ŋ: 86.7 (50 %), 90.8 (75 %), 89.6 (100 % load

Voltage, V 230 400 500-550 690 1000
Nominal current, A 19.7 11.3 9.0-10.8 6.6 4.5

Starting method and motor protection

XJS 50 AT: Direct on line start (DOL 400-550 V) with built in AquaTronic unit, which automatically adjusts phase order by dual contactors, ensuring correct motor rotation. Soft start is built in with the AquaTronic unit at 230 V, where three thyristors reduces start current to three times the nominal current. Here two relays ensures correct motor rotation. Soft start is available as option at 400 V. The AquaTronic unit monitors motor temperature, by use of NTC thermistors built into stator windings, and stops the motor at high temperature. It will also stop the motor at high amperage or if a phase is missing.

XJS 50: Direct on line start with built in contactor. Pumps to be used with VFD or 1000 V must have terminal block instead of contactor. Thermal switches (140 °C, ±5) built into the stator windings are con-nected to the contactor and stops the pump at high temperature.

Power cable

20 m type H07RN8-F (standard cable):
4 x 2.5 sq.mm. (230 V)
4 x 1.5 sq.mm. (400-690 V)

20 m type NSSHÖU.../3E (heavy duty cable):
3x2.5+3x2.5/3E+3x1.5 (3 control cables included) (1000 V orterminal block)
3x2.5+3x2.5/3E (230 V)
3x1.5+3x1.5/3E (400-690 V)

Shaft seal

Double mechanical seal in oil bath.
Primary seal: Silicon carbide on silicon carbide.
Secondary seal: Silicon carbide on carbon.


Upper bearing: Single-row deep groove ball bearing.
Lower bearing: Double angular contact ball bearing.

Discharge connections

2 ½", 3" (standard), 4" hose connections.
2 ½", 3", 4" G/B.S.P. threaded connections.


59 kg (without cable)

Options and accessories

AquaPlug. AquaTronic control panel.
Level sensor. Service data kit.
Zinc anodes. Surface protection coating.
Floatation ring. Discharge connection accessories and hose.

Pump control

    XJS 50 AT
Features XJS 50 AT AT + Level Sensor AT + AquaPlug / AquaTronic Control Panel AT + AquaPlug / AquaTronic Control Panel + Level Sensor Service Data Kit Read out
Run mode X X X X X  
Integrated start equipment X X X X X  
Automatic direction of rotation   X X X X  
Motor protection high temp X X X X X X
Motor protection high amp   X X X X X
Protection against missing phase   X X X X X
Level control     X   X  
Dry run protection     X   X  
Automatic restarting     X   X  
Stop mode       X X  
E-mode (Automatic stop/run)     X   X  
Indication of water in oil       X X X
Indication of low motor insulation       X X X
Indication of high or low voltage       XX XX X
Indication of high temperature       XX XX X
Indication of high amp       XX XX X
Indication of phase unbalance       XX XX X
USB cable connection   X X X X X
Crash log (10 latest)           X
Documentation (spare part list, workshop manual)           X

XX = Fault indication when pump is automatically stopped to protect the motor.


Description Material EN ASTM
Castings Aluminium EN 1706:AC-43100  ASTM AlSi10mg
Casing / Jacket Stainless steel 10088:X5CrNi18-10 (1.4301)  AISI 304
Rotor shaft Stainless steel 10088:X20Cr13 (1.4021)  AISI 420
Impeller / Wear ring White cast iron EN-GJN-HV600(XCr23)  ASTM A 532: Alloy III A
Fasteners Stainless steel 10088:X5CrNiMo 17122 (1.4401) AISI 316
Wear parts / O-rings Nitrile rubber    
Coating 2 component epoxy paint 120 μm