Solar pump inverter & drive cabinet
A cabinet that takes DC from the PV array and drives your existing three-phase pump motor, with the DC and AC protection built in. If you already have the pump, or have chosen it, this is the part you need from us. We quote it against your pump nameplate.
Supplied FOB China through audited partner factories. We do not install or commission; that stays with your local contractor.
What the cabinet does
Tracks the array
Follows the maximum power point as irradiance changes through the day, and varies motor frequency so the pump runs on whatever the array can give.
Drives the motor
Variable frequency output to a standard three-phase induction motor. The pump does not have to be a special solar model.
Stops before damage
Dry run, tank full, overload and overtemperature all stop the pump rather than let it run itself into trouble.
Electrical window
The array has to sit inside these limits on the coldest morning and the hottest afternoon at your site, not only at standard test conditions. That is why we ask for the site location before quoting.
| PV input window | Two ranges. The low window runs 150 – 450 V, the high window 350 – 780 V. Which one suits you depends on how the array is strung. |
| Where to put the string Voc | Aim for 360 – 430 V on the low window and 620 – 750 V on the high one. That leaves room for a cold morning to lift the array voltage without going over. |
| AC input | 110 V, 220 V or 380 V, 50 or 60 Hz, for sites that also have grid or a generator. |
| Motor output | 0 – 599 Hz, so the pump speed follows whatever the array can give through the day. |
| Power range | 0.75 kW to 55 kW single or three phase, and 37 kW to 200 kW on the larger three-phase frame. |
| Cooling | Forced air. |
The quotation carries the string sizing for your site: how many modules per string, and the array voltage at your record low and record high module temperature.
Cabinet size by power band
Check this early. The step at 37 kW is a big one and it changes what kind of room or shelter you need.
0.75 – 11 kW
600 × 1000 × 350 mm
W × H × D · Compact wall-space footprint
15 – 30 kW
800 × 1000 × 350 mm
W × H × D · Same depth, wider frame
37 kW and above
800 × 2000 – 2200 × 600 – 800 mm
W × H × D · Floor-standing; plan the room around it
Protection comes in two separate layers
Offers often merge these into one list, and then the cabinet turns out not to have the breakers you assumed were in the price. They are separate things.
Inside the drive
Electronic protection, part of the drive itself
- Undervoltage and overvoltage
- Input phase loss
- Overload and overcurrent
- Thermal / overtemperature
- Short circuit
- Dry run (no water)
- Tank full / overflow
- Low-irradiance sleep and wake
Added in the cabinet
Physical devices wired around the drive
- AC circuit breaker
- DC circuit breaker
- Surge protective device
- Temperature-controlled cooling fan
Device ratings are selected per project against the array and motor, and confirmed on the drawing that goes with the quotation.
Site conditions and enclosure rating
Dust protected, and protected against water splashing from any direction. Suitable for an equipment room or a sheltered outdoor position.
IP54 is not a washdown or driving-rain rating. If the cabinet will stand fully exposed, say so and we specify a higher enclosure rating for that project. It is a different cabinet, not a different label.
Two ratings, two different things. The drive electronics inside carry their own enclosure rating, an indoor one. That is normal, because they sit inside the cabinet. The IP54 figure describes the cabinet.
Be careful with offers that quote a single IP number without saying which part it belongs to. An IP figure lifted from a drive datasheet says nothing about the box it is mounted in.
Temperature
The drive electronics carry a wide ambient rating, but air inside a closed cabinet runs hotter than the air outside it. We size the installation against a working limit at the drive air inlet rather than the headline ambient figure, and we do not assume continuous operation at the top of the range. On a hot-climate project this usually means planning ventilation or shade for the cabinet, which is worth deciding before the room is built.
Grid, generator or solar only
Having a grid supply on site does not automatically mean you need a hybrid cabinet. What matters is what that supply has to do. Three answers, three different bills of materials, three different prices:
Solar only
The pump runs when the array can run it, and stops when it cannot. Simplest and cheapest.
Automatic transfer
The cabinet switches between solar and the other supply as conditions require. One source at a time, not the two blended.
Standby only
The other supply is there for occasional use and switched manually. Less equipment than automatic transfer.
Tell us which of the three you want on the enquiry form. It is the single answer that moves the cabinet price most, and it is the one buyers most often leave out.
What we need to quote
Send us
- •Pump nameplate. A photo is fine, and it is the most reliable input we can get
- •Motor voltage and phase
- •Head and flow, or borehole depth and daily water demand
- •Site city or coordinates
- •What is on site now: grid, generator or nothing, and what it has to do
Not in our scope
- •The pump and motor, unless you ask us to include them
- •The equipment room or shelter
- •Installation, wiring on site and commissioning
- •Local electrical connection and permits
Frequently asked questions
What does a solar pump inverter actually do?
It takes DC from the PV array, tracks the maximum power point as irradiance changes through the day, and outputs a variable frequency to drive the pump motor. The pump speeds up and slows down with the sun instead of stopping and starting, and the drive stops it on dry run, tank full, overload or overtemperature.
Does my pump have to be a special solar model?
No. The cabinet drives a standard three-phase induction motor. What we need from you is the pump nameplate: motor power, voltage and phase. A photo of it is the most reliable input we can get.
What is the difference between IP20 on the drive and IP54 on the cabinet?
They describe two different things. The drive electronics carry their own enclosure rating, an indoor one, which is normal because they sit inside the cabinet. IP54 describes the cabinet: dust protected and protected against splashing water from any direction. Be careful with offers that quote a single IP number without saying which part it belongs to.
Is IP54 enough for an outdoor cabinet?
It suits an equipment room or a sheltered outdoor position. It is not a washdown or driving-rain rating. If the cabinet will stand fully exposed, say so and we specify a higher enclosure rating for that project. It is a different cabinet, not a different label.
Can the cabinet run on grid or a generator as well as solar?
Yes, with AC input selectable at 110 V, 220 V or 380 V. What matters is what that supply has to do: nothing, transfer automatically, or stand by for manual use. Those are three different bills of materials and three different prices, so tell us which on the enquiry form.
What do you need to quote a drive cabinet?
The pump nameplate, the motor voltage and phase, the head and flow or the borehole depth and daily demand, the site city or coordinates, and what power is on site now. The location matters because the string voltage has to stay inside the drive window at your record low and high module temperature.
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Need project-specific engineering support?
Free CAD layout, wind/snow load calculations, and BOM review included with project orders.
Quote a drive cabinet
Send the pump nameplate and the site location and we can start. The rest can follow.