VFD for a single-phase "Vodoley" pump: wiring and setup

"Vodoley" is a pump brand, not a wiring scheme

"Vodoley" is a common name for Ukrainian household centrifugal and vortex pumps with a single-phase 220 V motor. Such a motor has two windings — main (run) and start — with a phase-shifting capacitor wired between them. It is the capacitor that creates the phase shift needed to start and run the motor.

Why fit a VFD to a "Vodoley" pump at all? Most often — to hold steady pressure in the system without water hammer, to start the motor smoothly (less stress on the mechanics and the grid), and to remove the characteristic start-relay "clicks" and voltage dips at startup. Soft starting also noticeably extends pump life: the sharp current surge of a direct start is one of the causes of winding and bearing wear.

To power such a pump from a 220 V mains supply you need a single-phase 1×220 V VFD — for example, the Veichi AC01 series, compact single-phase models made specifically for household pumps. Single-phase drives are sensitive to input phasing — connect the supply strictly per the terminal markings (L/N), not at random.

Two wiring methods — and which to choose

There is a myth around the "Vodoley" that the capacitor must be thrown out for a VFD. In practice that is not true. There are two working methods, and you should almost always start with the first.

Method 1 (primary) — keep the capacitor. Connect the pump to the VFD "as is", without dismantling anything. This is what we do in 95–99% of cases with "Vodoley" and "Pedrollo" — and have done for many years, without issues. It is the simplest and fastest path.

Method 2 (fallback) — capacitor-free. The capacitor is removed, and the motor's two windings are driven directly from the three VFD outputs. This method is needed only when the motor is actually a symmetric three-phase one with accessible windings, or when a specific capacitor does not "get along" with the VFD. It is the exception, not the default.

Why not start by removing the capacitor? Because in an ordinary single-phase motor it is the capacitor that creates the phase shift — remove it from a working scheme and the motor simply will not start (the phase-shift angle is broken). So we touch the capacitor only when we know for sure we are dealing with symmetric windings.

Method 1 (primary): wiring with the capacitor

This is the option we recommend first. Nothing to dismantle or rewire — the capacitor stays in the system, as it was.

Scheme: mains 220 V → capacitor (in the pump's stock box) → VFD → pump. That is, the VFD is inserted after the capacitor, and the drive output goes to the pump motor. The motor windings are not rewired.

Before the first start, check and tighten all screw terminals on the terminal block — vibration with a loose contact typically leads to power-module burnout. If the old pump scheme had a mechanical thermal relay, remove it from the circuit after installing the VFD: the drive has its own digital motor protection that works more accurately.

Settings are as in the table below (V/F mode, output phase-loss protection disabled via F10.20). After startup, be sure to measure the motor's running current and compare it with the rated value on the nameplate.

When the capacitor does not "get along" with the VFD. In roughly 5–10% of cases (and more on compressors) a particular capacitor works poorly with the VFD's PWM output: it heats up and prevents the motor from reaching steady speed. Here is the key point: we do not "fix" this by removing the capacitor at random. If you fall into that percentage — choose a more reliable solution (a three-phase motor, see the end of the article) or, if the motor is symmetric, try Method 2. And if your particular pump still cannot be started reliably — we refund the drive: making you "fight" the equipment is not something we consider fair. For "Vodoley" and "Pedrollo" the track record is practically trouble-free.

Method 2 (fallback): capacitor-free for a symmetric motor

We use this method only when the motor is actually a symmetric three-phase one whose windings are tied together through a capacitor, or when Method 1 failed because of an incompatible capacitor. Confirm this with a winding measurement before installation.

Step 1. Identify the windings with a multimeter

A single-phase motor's terminal box usually has three or four leads. Until you know which winding is which, you cannot connect the VFD — swapped leads will give either no torque or reverse rotation with overload. Take a multimeter in resistance (Ohm) mode and ring out the leads in pairs.

Common lead. Has an electrical connection to both other leads. This is the point where the windings are joined inside the motor.

Main (run) winding. Has the lower resistance. It is rated for continuous current and does the main work.

Start (auxiliary) winding. Has the higher resistance — wound with thinner wire and meant only to create starting torque.

Write down three readings: for example, A–B 4 Ω, A–C 7 Ω, B–C 11 Ω. The highest resistance (B–C) is the sum of two windings through the common point, so lead A is the common one. Of the other two, the lower resistance indicates the main winding, the higher one the start winding.

A few practical notes. First, if the motor has four leads, two of them may already be joined inside or under the capacitor — first dismantle the old scheme and find where the capacitor's "whiskers" went. Second, cheap multimeters measure small resistances (1–3 Ω) poorly: if the difference between windings is small, ring out each pair several times and rely on a stable ratio. Third, label the leads immediately — they are very easy to mix up after disconnecting the capacitor.

Step 2. U-V-W wiring scheme

Once the windings are identified, the installation is simple. First remove the capacitor from the motor scheme, then connect the three leads to the VFD output power terminals:

• Common lead → terminal V;
• Main (run) winding → terminal U;
• Start (auxiliary) winding → terminal W.

That is, the common lead always goes to the middle phase V, and the two windings split to U and W. If the pump runs in the wrong direction after startup — do not fiddle with parameters, just swap the connections on U and W.

Veichi AC01 parameters

The settings are the same for both methods. On a single-phase motor (with or without a capacitor) the drive "sees" an asymmetric load and by default treats it as an output phase loss — so, besides selecting the control mode, you need to deliberately disable output phase-loss protection. All codes below are taken from the official AC01 drive manual.

Why F10.20 rather than some F09-group parameter? Some materials and chats for single-phase motors mention "F09.13 = 0". The official AC01 manual has no such parameter — group F09 is responsible for auxiliary control, while phase-loss protection is exactly F10.20 in protection group F10. If you disable the "wrong" parameter, the drive will still stop with a fault. Always rely on the manual for your specific series.

After the first start, watch the behaviour: the pump should smoothly reach the rated 50 Hz without jerks and without protection faults. The basic start/stop and frequency-source settings for the AC01 are covered in detail in a separate article — Veichi AC01 VFD setup.

One more practical tip — do not push the pump above 50 Hz. The temptation to "add pressure" by ramping to 55–60 Hz ends in overheating: the start winding is not rated for prolonged operation at raised voltage. Keep the working range within 30–50 Hz, and adjust the needed pressure by pump selection and settings, not by "over-twisting" the frequency. If the motor hums noticeably at low speeds — that is normal for V/F mode; a sharp metallic whine is removed by slightly raising the PWM carrier frequency.

When neither method fits — switch to three-phase

Honestly: some household single-phase motors physically work poorly from a VFD — both with and without a capacitor. There is a limit beyond which there is no point fighting.

After startup, measure the motor's running current and compare it with the rated value on the nameplate:

Current within the rating — the motor is compatible, it can be operated.

Running current exceeds the rated value by more than double (>2×) or the motor overheats — stop operation. The winding construction of such a motor is not designed to run from a VFD.

In that case the most reliable path is to fit a three-phase pump (or three-phase motor) and power it from an ordinary single-phase VFD. We covered how this works here: connecting a three-phase motor to a single-phase mains. And to decide on the drive type — single-phase and three-phase frequency converters.

Separately, about sizing the drive by current. On a single-phase motor the current distribution between windings is uneven, so take the VFD with headroom — go not by the rated power in kW, but by the drive's rated current, which should exceed the motor's running current by at least 25–30%. If the motor is 0.75 kW with a running current of about 5 A — take a drive whose rated output current is 6–7 A or higher.

Frequently asked questions

Do I need to remove the capacitor on a "Vodoley" before connecting a VFD?

No, in most cases you do not. The main working method is to keep the capacitor and connect the pump "as is". The capacitor is removed only in a special case: when the motor is in fact a symmetric three-phase one (tied through a capacitor), or when a specific capacitor does not "get along" with the VFD. Start with the "with capacitor" scheme.

Which VFD do I need for a single-phase 220 V pump?

A single-phase drive with a 1×220 V input — for example, the Veichi AC01 series. See the category single-phase 220 V VFDs. Pay attention to the drive's rated current: it must cover the motor's running current with headroom.

Why does the VFD throw a phase-loss fault right away?

Because a single-phase motor is an asymmetric load for the VFD output, and the protection treats it as an output phase loss (faults of the E.oLF type). On the AC01 this is solved by the parameter F10.20 = 20, which disables output phase detection.

The pump turns the wrong way — what should I do?

If you wired it with the U-V-W scheme (Method 2) — swap the two wires on terminals U and W. The direction of rotation will change without touching the parameters.

How do I make the VFD hold steady pressure?

For automatic pressure control the drive runs in PID mode with a pressure sensor (4-20 mA) and a "sleep" mode when there is no water draw. We have covered the PID parameters, the sleep threshold and the pressure-sensor scheme for Veichi separately: Veichi VFD setup for a pressure sensor.

Will this method work for a borehole (submersible) pump?

The principle is the same, but a borehole adds its own nuances — a long cable, voltage drop, dry-run protection. That is a separate topic: Veichi VFD for a borehole pump.

If you are unsure about the compatibility of a specific motor or about sizing the drive by current — write to us with the pump's nameplate, and we will suggest a model and safe settings for your case.