Pump Drive
Motor, Variable Speed Drive & Coupling Selection
For a pump drive the critical numbers are the duty point, the maximum impeller diameter and the medium. The motor has to be rated for the end-of-curve condition, not just today's operating point, and the coupling and starter follow from there.
Send us the duty point, medium and power supply. We select the motor, drive or fluid coupling, and controls, and quote them matched to the pump you are buying or replacing.
What we need from you to select this drive
The more of this you send, the faster and more accurate the selection. If you only have part of it, send what you have — we will tell you what is still missing.
Duty data and site conditions
| Pump type | End-suction, multistage, axial or radially split, slurry, submersible, progressive cavity |
|---|---|
| Duty point | Flow in m³/h, head in m, and whether it is a single or variable duty |
| Medium | Density, viscosity, solids content and size, temperature, corrosiveness |
| NPSH | NPSH available at site, and the required NPSH margin |
| Speed and power | Pump speed in rpm, absorbed power, and maximum impeller diameter |
| Power supply | Voltage, frequency, phases, permitted voltage drop, medium-voltage requirement |
| Control method | Fixed speed, VSD, or fluid coupling; required turndown and control signal |
| Site conditions | Ambient temperature, altitude, indoor or outdoor, hazardous area classification |
How we select it
- 1
Confirm the duty point and the maximum impeller diameter so the motor covers the end-of-curve power.
- 2
Correct the absorbed power for density and viscosity where the medium is not water.
- 3
Rate the motor with the appropriate margin and check the starting current against the permitted voltage drop.
- 4
Select the control method — VSD, fluid coupling or fixed speed — against the turndown and the process requirement.
- 5
Match the coupling, baseplate and controls, then quote the package with the pump.
Selection points that decide the outcome
Rate for the end of the curve
A motor rated only for today's duty point will trip when the impeller is changed or the valve opens further. Rate for the maximum impeller diameter.
Viscosity changes everything
Above roughly 30 cP the pump curves and the absorbed power move significantly. State the viscosity at the operating temperature.
NPSH margin
A drive package cannot fix a suction problem. Confirm NPSHa exceeds NPSHr with margin before the pump and drive are finalised.
VSD versus fluid coupling
A VSD gives control and energy saving across the turndown; a fluid coupling gives soft starting and overload protection at lower cost. The right choice depends on the duty profile.
Minimum flow at low speed
Running a pump well below its best efficiency point brings recirculation and heat. Confirm the minimum continuous flow at the lowest controlled speed.
An indicative package
An example of how a selection comes together. Your figures will differ — this is to show the level of detail we return with a quotation, not a fixed configuration.
Duty
KSB Etanorm end-suction pump · 400 m³/h at 50 m · water at 60 °C · outdoor, 45 °C · 50 Hz
Package
- Motor: ~90 kW, 4-pole, IE3 or IE4, IP55, rated for the maximum impeller diameter
- Control: Siemens SINAMICS G120X or ABB ACS580 with pump-specific control functions
- Coupling: Flender N-EUPEX or ELPEX flexible coupling with spacer if required
- Alternative: Flender FLUDEX fluid coupling where soft starting and overload protection are preferred
- Monitoring: temperature and vibration monitoring, and control integration via SIMATIC or B&R
What we supply for this duty
Pumps
- KSB Etanorm, Etanorm MyFlow and Etanorm Pro standard pumps
- KSB MegaCPK chemical process pumps, −40…+400 °C
- KSB Multitec multistage, Magnochem magnetic drive, Amarex submersible
- Sulzer API 610 / ISO 13709 process pumps
- Sulzer axially and radially split multistage, vertical inline, slurry and PC progressive cavity pumps
Motors
- Innomotics SIMOTICS low-voltage and medium-voltage motors
- WEG W22 and W40
- ABB IEC and NEMA motors, IE5 SynRM
- KSB SuPremE synchronous reluctance motors, IE4 / IE5
Variable speed drives
- KSB PumpDrive and PumpMeter
- Siemens SINAMICS G120X pump-optimised drives
- ABB ACS580 and ACS880
- WEG CFW11 and CFW701
Couplings and fluid couplings
- Flender N-EUPEX, ELPEX, ARPEX and ZAPEX couplings
- Flender FLUDEX fluid couplings
Seals, valves and control
- Sulzer mechanical seals
- KSB ISORIA and DANAÏS valves
- Siemens SIMATIC and B&R X20 control integration
Ratings we can supply
Typical ratings available
| Flow | KSB Etanorm up to 2,321 m³/h; Sulzer ranges cover larger process duties |
|---|---|
| Temperature | KSB MegaCPK −40…+400 °C; state the medium temperature for seal selection |
| Motor power | 0.12 kW to multi-megawatt; medium-voltage for large pump duties |
| Medium-voltage drive | Innomotics Perfect Harmony GH180: 2.3 – 11 kV, 0.12 – 25 MW |
| Control | Fixed speed, VSD, or fluid coupling, selected against the required turndown |
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Related applications
Other Brands Available on Request
Beyond the brands shown here, we also source and supply spare units and parts for most international and Chinese industrial brands. Not sure what you have? Send us a photo of the nameplate — we will identify the unit and quote the original part.
Why work with us
- We select the whole drive train — motor, gear unit, coupling, starter and brake — as one matched package.
- You send the duty data; we return the ratings, service factors and alternatives in writing.
- We supply Siemens, Innomotics, Flender, ABB, WEG and B&R, so selection follows your duty, not one catalogue.
- Spare parts and replacements for the same units are available afterwards.
Service & support
Remote and on-site support available, from installation supervision to commissioning and troubleshooting.
What we need from you to quote
For replacements, send a nameplate photo — we identify the exact unit and quote the original part.
- Duty data — power, torque, speed, flow or head, and duty cycle
- Supply voltage, frequency and starting method
- Preferred brand, and your required delivery window
- Quantity, destination port and required delivery date
Answers before you ask
Frequently asked questions
Can you supply the pump and the drive as one package?
Yes. We supply KSB and Sulzer pumps together with the matched motor, variable speed drive or fluid coupling, coupling and controls, quoted as one package.
Should I use a variable speed drive or a fluid coupling on my pump?
It depends on the duty profile. A variable speed drive gives control and energy saving across the turndown range, while a fluid coupling gives soft starting and overload protection at lower cost. Tell us the duty and we will recommend one.
Do you only supply the eight brands shown on your homepage?
No. We source and supply spare units and parts for most international and Chinese industrial brands, not only the eight brands shown on this site.
I do not know the exact model number. Can you still quote?
Yes. Send us a photo of the nameplate and we will identify the exact unit before preparing the quotation for the original part.
Do you supply genuine original manufacturer parts?
Yes. We supply genuine original manufacturer parts. Send us a photo of the nameplate and we can identify the exact unit before quoting, so you do not need to look up a model number.
Do you provide installation guidance, commissioning and after-sales support?
Yes. We provide installation guidance, commissioning support and after-sales support, remotely or on site depending on your project.
What is the delivery time?
Lead time depends on the product and configuration. We confirm the delivery schedule together with the quotation, so you have a firm date before you order.
Which export documents and certificates can you provide?
We can provide applicable CE and ISO documentation, certificates of origin, packing lists and test reports according to the requirements of your destination country.
What payment terms and incoterms do you work with?
We accept T/T and L/C payment, and quote FOB, CIF or EXW terms to suit your project.
Send the duty data and we will select the package
We return a selection with the ratings, service factors and alternates stated — so you can compare before you buy.
Request a Quotation