The TSURUMI 50NHC21.5 is a submersible cutter sewage pump from the NHC series of Tsurumi's TSURUMI UNIVERSE brand. It has a 50 mm discharge and a 1.5 kW 2-pole three-phase motor. The NHC series is designed for raw sewage, wastewater and heavy-duty industrial drainage where oversize fibrous material would clog an ordinary pump: tungsten carbide edges on the impeller rotate against a serrated suction port and cut incoming fibres, keeping the discharge pipe and valves clear.
The 50NHC21.5 is one of the smaller NHC models, weighing 41 kg free-standing. It suits sewage pits and small pump stations where flows are modest but the wastewater carries fibrous debris.
Selection note: the 50NHC21.5 is a cutter sewage pump, not a slurry pump or a site dewatering pump. Official data covers sewage, wastewater and fibrous solids only; it is not intended for sand slurry, construction-site mud or abrasive liquids. For more head on a 50 mm discharge, see the 50NHC22.2 (2.2 kW); for lower-head duties, see the 50NHC2.75 (0.75 kW).
Key features
- Cutter design against clogging: a semi-open two-vane impeller carries two brazed, sintered tungsten carbide alloy edges that rotate against the serrated suction port of the suction cover, cutting fibrous material before it is discharged.
- Double inside mechanical seals: silicon carbide (SiC) faces running in an oil chamber. Tsurumi's catalogue states SiC offers five times the corrosion, wear and heat resistance of tungsten carbide.
- Oil Lifter (Tsurumi original design): keeps the seals lubricated and cooled even when the oil level falls to one-third of normal.
- Continuous-duty dry motor: 2-pole induction motor with class H insulation.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on overheating or overcurrent.
- Anti-wicking cable entry: limits water creeping along the cable cores into the motor if the cable sheath is damaged.
- Guide rail option: the TOS50NHC21.5 guide rail version lets the pump be raised and lowered for maintenance without anyone entering the sump.
Applications
- Sewage pump stations and pits: sewage and wastewater containing fibrous debris
- Septic and purification tanks: raw water transfer
- Wastewater treatment facilities: wastewater transfer
- Flood prevention equipment: drainage pumping stations
- Recreational facility reservoirs: drainage
Performance
The figures below are read from the official 50 Hz performance curve. They are approximate and are not guaranteed duty points. The maximum head of about 19.5 m is the head at zero flow; the maximum capacity of about 0.43 m³/min (about 430 L/min) is the end point of the curve, at about 7.8 m head. The two never occur together: actual flow falls as total head (static head plus pipe friction loss) rises. Select the pump from the performance curve using your site's total head, and avoid continuous running on the dashed (low-flow) section of the curve.
Technical specifications
TSURUMI 50NHC21.5 technical specifications (50 Hz)
| Item | Specification |
|---|
| General |
|---|
| Model | 50NHC21.5 |
|---|
| Series | NHC (TSURUMI UNIVERSE, submersible sewage pump with cutter impeller) |
|---|
| Discharge bore | 50 mm |
|---|
| Discharge connection | Threaded JIS 10kg/cm² flange |
|---|
| Guide rail model | TOS50NHC21.5 (ordered separately) |
|---|
| Hydraulic performance (approx., read from curve) |
|---|
| Max. head (at zero flow) | approx. 19.5 m |
|---|
| Max. capacity (curve end point) | approx. 0.43 m³/min (approx. 430 L/min) at approx. 7.8 m |
|---|
| Electrical |
|---|
| Motor output | 1.5 kW |
|---|
| Motor | 2-pole dry-type induction motor, continuous duty, insulation class H |
|---|
| Speed | 3,000 min⁻¹ (50 Hz) |
|---|
| Power supply | 3-phase 50 Hz (voltage as per nameplate) |
|---|
| Starting method | Direct-on-line (D.O.L.) |
|---|
| Motor protection | Built-in circle thermal protector (CTP) |
|---|
| Leakage sensor | None |
|---|
| Cable | 6 m, chloroprene rubber |
|---|
| Seals and lubrication |
|---|
| Shaft seal | Double inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
|---|
| Oil seal | NBR |
|---|
| Lubricant | Turbine oil ISO VG32, 940 ml |
|---|
| Materials |
|---|
| Impeller | Semi-open two-vane, grey cast iron with tungsten carbide alloy edges |
|---|
| Suction cover | Ductile cast iron (serrated suction port) |
|---|
| Casing | Grey cast iron |
|---|
| Motor frame | Grey cast iron |
|---|
| Shaft | 420 stainless steel |
|---|
| Dimensions and weight |
|---|
| Dimensions (L × W × H) | Free-standing 451 × 238 × 468 mm; guide rail fitting 633 × 238 × 534 mm |
|---|
| Dry weight (excl. cable) | Free-standing 41 kg; guide rail fitting 37 kg (excl. duckfoot bend) |
|---|
Sources: TSURUMI UNIVERSE NH-series submersible sewage pump catalogue (IA143, 50 Hz) and the NHC product page on tsurumiuniverse.com. Performance figures are read from the official curve and are for reference only. Maximum liquid temperature, maximum solids passage and pH range are not published; voltage and rated current are as per the nameplate. Tsurumi states that specifications may change without notice, so request the factory specification sheet before use.
NHC series comparison
Tsurumi NHC cutter sewage pump comparison (50 Hz, approx. curve readings)
| Model | Discharge | Power | Max. head (approx.) | Max. capacity (approx.) |
|---|
| 50NHC2.75 | 50 mm | 0.75 kW | 16 m | 0.30 m³/min |
|---|
| 50NHC21.5 (this product) | 50 mm | 1.5 kW | 19.5 m | 0.43 m³/min |
|---|
| 50NHC22.2 | 50 mm | 2.2 kW | 23.5 m | 0.55 m³/min |
|---|
| 50NHC23.0 | 50 mm | 3.0 kW | 32 m | 0.50 m³/min |
|---|
| 50NHC23.7 | 50 mm | 3.7 kW | 32 m | 0.67 m³/min |
|---|
| 80NHC22.2 | 80 mm | 2.2 kW | 22 m | 0.67 m³/min |
|---|
| 80NHC23.0 | 80 mm | 3.0 kW | 16.7 m | 1.25 m³/min |
|---|
| 80NHC23.7 | 80 mm | 3.7 kW | 28 m | 1.0 m³/min |
|---|
| 80NHC211 | 80 mm | 11 kW | 49 m | 0.99 m³/min |
|---|
Optional accessories
- Guide rail fitting: order the TOS50NHC21.5 guide rail version. The set includes a duckfoot bend, guide support (with bolts and nuts), guide hook, 5 m lifting chain with shackles and a JIS 10kg/cm² flange. The guide pipe is not supplied and must be sourced locally.
- Float switches: Tsurumi MC-2 heavy-duty float switch (with shock absorber, for liquids with much suspended solids and scum, NO or NC contact selectable) or MT-1 economy float switch (SPDT contact, for filling or emptying control). Three-phase pumps must be connected through a control panel.
- Control panel: for direct-on-line starting with overload and short-circuit protection.
- Lubricant: turbine oil ISO VG32 (940 ml for this model).
- Pipe fittings: the discharge is a JIS 10K flange, so pipe flanges and fittings must match.
Safety and installation
- Three-phase electrical connection must be made by a registered electrical worker in line with local regulations, with proper earthing and overload and short-circuit protection.
- Check the rotation direction of the three-phase pump before first use.
- Lift the pump by its handle or lifting chain. Never lift it by the power cable.
- Isolate and lock out the power before inspecting or clearing the suction cover. The tungsten carbide edges and serrated suction cover are sharp.
- Do not run the pump continuously on the dashed (low-flow) section of the performance curve.
- No explosion-proof rating is published, so do not use the pump in flammable or explosive atmospheres.
- Sewage pits are confined spaces with hydrogen sulphide and oxygen-deficiency hazards. A guide rail installation allows the pump to be serviced without entering the pit.
Wear parts and routine checks
- Main wear parts: impeller cutter edges, suction cover, mechanical seals and oil seal.
- The Oil Lifter only keeps the seals lubricated down to one-third of the normal oil level, so check the oil level and condition in the oil chamber regularly. If the oil is cloudy or contains water, have the shaft seals inspected promptly.
- Check the impeller cutter edges and the serrated suction cover for wear regularly. If cutting performance or flow drops, have them inspected or replaced.
