Electric Motors for Stone Cutting and Calibrating Line Water Pumps

On marble cutting and calibrating lines the water pump supplies cooling water to the blades and abrasive heads, carries used muddy water to the settling pond or treatment plant, and sends clear water back to the machines. The part that turns the pump impeller is the electric motor. In maker data sheets, water pump motors on stone machinery start at half a horsepower on small benches, reach 15–30 kW on a factory’s main supply and return pumps, and go higher on large treatment plants.

Scope: DRG Motor is a manufacturer, supplier and seller of electric motors. We do not sell pump casings, impellers, seals, booster sets, submersible pumps, filter presses, clarifiers, gearboxes, hydraulic units or drives (inverters); spindles and servos are not in our range either. What we sell is the dry-type three-phase motor that turns a surface pump. The models are on Buy Electric Motors Online.

The water circuit of a marble plant and what each pump does

Bridge saws, gang saws, calibrating and polishing machines all work wet. One bridge saw data sheet gives a water consumption of 3.5 m³/h; once several machines and a calibrating line run together, the plant needs tens of cubic metres per hour. That water is not thrown away after one pass: it is collected, the slurry is separated and the water is reused. Each link of this loop has its own pump.

Cooling water supply and circulation

The pump that sends water from the clear water tank to the machines is the heart of the line. If water stops, the blade overheats, segments burn and cutting halts. These pumps usually run continuously; flow follows the number of machines, head follows pipe length and nozzle pressure at the machine. Some machines also carry a small circulation pump in their own frame.

Slurry and settling pond pump

Water returning from the machines contains stone dust and abrasive. It is pumped from a collecting pit to a settling pond or a clarifier (settling tank). Muddy water is abrasive; the pump impeller and casing are chosen for it, while the motor is sized from the power and speed the pump needs. The submersible pump often used in the collecting pit is outside our range; we cover that separately below.

Filter press feed and booster pump

Slurry thickened in the clarifier is pumped into a filter press and turned into cake. This feed pump works against a pressure that rises as the press fills. The filter press’s own hydraulic unit is a separate motor; we covered it in Filter Press Motor: Hydraulic Unit, Duty and Mounting. If a distant or elevated machine does not get enough pressure, a booster pump is added to the line; it too is a standard centrifugal pump with a motor.

Centrifugal surface pump and the motor connection

Most water pumps in marble plants are centrifugal and stand on the floor or at the pond edge. The motor joins the pump in one of two ways. The connection type is read from the pump label and the maker’s drawing; the exact mounting type is taken from the pump maker’s drawing.

Coupled layout: foot-mounted B3 motor

Pump and motor sit on a common baseplate with a flexible coupling between them. The motor is a foot-mounted B3. On replacement, shaft height H, shaft diameter and key, and foot hole dimensions are checked; coupling alignment must be redone with the new motor. A misaligned coupling ruins bearings quickly and increases seal leakage.

Close-coupled and flanged layout: B5 or B35

On small and medium pumps the pump casing bolts straight to the motor flange. Here the motor is B5 (flange only) or B35 (feet + flange). On some close-coupled pumps the impeller fits directly on the motor shaft; on such a pump the shaft length and end may be specific to the pump maker. Where a dimension falls outside standard IEC shafts and flanges, we compare it with our catalogue first.

How many kW is a stone machine water pump motor?

A) Pump and plant makers quote these motor ratings:

Depending on the maker’s model, flow and head, a single motor in this pump group ranges roughly from 0.37 to 30 kW; on the largest treatment plants one pump reaches 75 kW and pumps are installed in pairs. Total power figures in treatment plant sheets include auxiliaries such as the clarifier scraper and chemical dosing; do not read that total as the power of one pump. More flow or more head means more power.

B) Where DRG fits: our 2- and 4-pole motors, aluminium or cast iron, reach every surface pump size between 0.37 and 75 kW. What falls outside is submersible pumps, together with the pump casing and hydraulic parts.

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How is pump motor power calculated?

The power a pump needs at its shaft is P = ρ · g · Q · H / η_pump. ρ is water density, Q flow, H total head and η the pump efficiency, taken from the pump data sheet. Type flow, head and efficiency of your own pump into the pump and fan motor power calculator.

Example: a cutting line supply pump

Assumptions: 50 m³/h flow, 24 m total head, pump efficiency 0.62 and a 1.15 factor for muddy water and wear:

5.5 kW falls short of the 6.07 kW required, so 7.5 kW is chosen. If the pump sheet calls for about 2900 rpm, a 2-pole motor is the choice.

Effect of muddy water

Water drawn from a settling pond is denser than clean water. With the same formula at 30 m³/h, 18 m and 0.55 efficiency, clean water needs 2.68 kW while slurry at 1150 kg/m³ needs 3.08 kW. The gap widens as the slurry thickens; the motor is sized for the heaviest operating case.

Submersible pumps are not in our range: what we do cover

In submersible pumps lowered into a pit or pond, the motor is a sealed unit running under water together with the pump. These motors are not in the DRG range; our standard dry-type motor is not run under water. When a submersible pump motor fails, the usual answer is the pump maker’s own spare unit. What we cover are the motors of surface pumps installed at the pond edge. Whether a dry-installed surface pump could replace a submersible one, if the pit layout allows, can be assessed with the pump maker.

Speed, starting and the wet environment

2-pole or 4-pole?

On clean water and medium-pressure supply pumps, a 2-pole (about 2900 rpm) motor is common. Pumps handling water with slurry and abrasive also come in lower-speed designs to reduce impeller wear; the data sheet above gives two speed options for the same filter press pump. Which one is needed is written on the pump label; changing pump speed changes flow and head too.

Star-delta and inverter

A centrifugal pump presents a light load at start; started against a throttled valve, star-delta is usually enough. Our motors from 4 kW have 400/690 V windings and, connected in delta on 400 V, can run star-delta. An inverter is used when pressure or flow is to be held constant; we do not sell drives, but our motors run on a properly set one. For the methods, see our Motor Starting Methods: Star-Delta tool.

Splashing and motor position

A pump room is damp and wet. Our motors are IP55; still, keep the motor away from where seal leakage and hose water would hit it directly, and mount it on a raised plinth. A leaking seal can let water creep along the shaft into the motor; seal maintenance protects the motor too.

DRG motors: models for surface pumps

2-pole motors in the power sizes common on marble plant water pumps (current at 400 V):

In aluminium we go from 0.25 to 11 kW, in cast iron from 0.55 to 355 kW, at 1000, 1500 or 3000 rpm. Write the mounting you need on the order: B3, B5, B14, B34, B35 or a vertical V1, V3, V5, V6 version. A vertical shaft pump needs a motor ordered for the vertical position, and the pump maker has to confirm the axial thrust from impeller and shaft. More by pump type is on our Pump Motors page.

Live price table

Shop prices of our motors in sizes suited to cutting and calibrating line pumps are read live:

DRG MOTOR motors are guaranteed against material and manufacturing defects for 2 years from the delivery date (warranty certificate).

Motors in this power range

• DRG-100L-2 – 3 kW – 2895 rpm – 100L cast iron
• DRG-132S1-2 – 5.5 kW – 2930 rpm – 132S cast iron
• DRG-160M1-2 – 11 kW – 2945 rpm – 160M cast iron
• DRG-180M-2 – 22 kW – 2955 rpm – 180M cast iron
• DRG-180L-4 – 22 kW – 1470 rpm – 180L cast iron

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Browse the products, ask for a quote: filter by power and speed for your pump motor on Buy Electric Motors Online. A WhatsApp message with the pump label and the old nameplate is the quickest start; +90 (542) 666 11 11 works too.

Frequently asked questions

My marble cutting water pump motor burnt out: is the same kW enough?

Yes, if the pump and piping have not changed. Still check why it burnt: a blocked suction, a worn impeller, water entering the motor from the seal or a lost phase will strain the new motor too.

Which mounting type does a calibrating line pump motor need?

B3 for a coupled pump on a baseplate, B5 or B35 for a close-coupled pump. Comparing the pump’s flange and shaft dimensions with the old motor is the most reliable way.

Do you sell submersible pump motors?

No. We supply no submersible pump motors at all; we offer dry-type three-phase motors for surface pumps.

Send pump motor questions to info@drgmotor.com, ring +90 (542) 666 11 11 or use the contact page. All stone machine water pump motor options are on Buy Electric Motors Online.