Most submersible motors don’t burn because they are old. They burn because something went wrong while nobody was watching: the borewell ran dry at night, one phase went missing, or the motor kept running on overload. A fully automatic starter watches the motor for you. It starts the pump when power comes back and switches it off the moment something goes wrong, before the motor burns. Here is what “automatic” really means, and which BTCO starter fits your motor.
What is an automatic starter?
An automatic starter runs your submersible pump without anyone standing next to it. It starts the motor by itself when power comes back, and stops it by itself when something is wrong: no water in the borewell (dry run), too much current (overload), a missing phase (single phasing) or a fault in the supply or the cable. A fully automatic starter does all of this and starts the motor again once it is safe.
Manual starter, auto switch or fully automatic: what is the difference?
Many farmers start with a manual starter and add an auto switch or a single phasing preventer later. Each piece does one job. A fully automatic starter does all of them together:
| What happens | Manual starter | Auto switch / SPP added | BTCO fully automatic starter |
|---|---|---|---|
| Power comes back | Someone must press start | Auto switch starts the motor | Starts the motor after the delay you set |
| Borewell runs dry | Motor keeps running | Motor keeps running | Stops the motor (Dry Run Trip), restarts after the dry restart time |
| One phase goes missing | Motor keeps running | SPP trips the motor | Stops the motor (Mains Problem) |
| Motor draws too much current | Overload relay, if set right | Overload relay, if set right | Stops the motor (Overload Trip) |
| Earth or cable fault | No | No | Stops the motor and shows the fault |
| Tells you why it stopped | No | No | Shows the reason on the display |
| Control from your phone | No | No | Yes, with the BTCO GSM Module |
What a BTCO fully automatic starter does, step by step
- Power comes back: the starter waits for the auto start delay you set (5 to 240 seconds on the DOL-03), then starts the motor on its own. A star delta starter starts the motor in star and changes over to delta after the delay you set, so the starting current stays low.
- While the motor runs: the MPAU unit inside the starter keeps watching the current and the supply, and shows the volts and amps on its digital display.
- Something goes wrong: it switches the motor off on dry run, overload, single phasing, supply faults (a cut wire or a blown fuse), earth faults, current imbalance and cable faults: the faults that burn submersible motors.
- It tells you why: the display shows the reason, such as Dry Run Trip, Overload Trip or Mains Problem.
- It starts again when it is safe: after a dry run trip, the starter waits for the dry restart time you set, so the borewell can refill, and then starts the motor again by itself.
Set the auto start delay on your starter with this short video:
Why farmers need an automatic starter
In many villages, three phase power comes in shifts, often at night. With a manual starter, someone has to walk to the field every time the power comes back, and nobody is there when the borewell runs dry at 2 a.m. An automatic starter starts the motor as soon as power returns, so you don’t lose watering time, and it protects the motor through the night, so you don’t wake up to a burnt motor and days without water.
Automatic starter with timer and water level control
- Timers: the DOL-03 and FASD-03 come in a timer + WLC variant with normal, cyclic and RTC (real time clock) timers (how the timers work). The Single Phase Domestic starter has timers built in.
- Water level control: the Single Phase Domestic starter starts the pump when the tank is low and stops it when the overhead tank is full or the sump is empty. The DOL-03 and FASD-03 timer + WLC variant does the same with BTCO magnetic water level sensors (how the water level controller works).
- Timers from your phone: with the BTCO GSM Module fitted, any BTCO starter can run on the 4 timer modes in the BTCO Starters app, including the Combined starters, which have no built-in timers.
Which BTCO automatic starter does your motor need?
| Your motor | Your power supply | BTCO starter |
|---|---|---|
| 3 phase, single cable, 3–10 HP | 3 phase | DOL-03 fully automatic DOL starter |
| 3 phase, double cable, 7.5–30 HP | 3 phase | FASD-03 fully automatic star delta starter |
| 3 phase, single cable, 3–10 HP | Juice line, 2 phase or 3 phase | DOL-2/3 Combined juice starter |
| 3 phase, double cable, 7.5–25 HP | 2 phase or 3 phase (juice line up to 10 HP) | FASD-2/3 Combined star delta starter |
| Single phase, 2–5 HP | Single phase | FASP-01 fully automatic single phase starter |
| You already have a 3 phase DOL or star delta starter | 3 phase | MPAU auto start unit and motor protection device |
Single cable or double cable? Read DOL vs star delta: which one does your motor need.
Already have a starter? Make it automatic with the MPAU
You don’t always need a new starter. The BTCO MPAU fits 3 phase DOL and star delta starters for motors up to 30 HP. It does the job of an auto switch and a single phasing preventer together, and adds dry run, overload, earth fault and cable fault protection, a digital display and an auto start delay. It is the same unit that runs every BTCO 3 phase starter.
Go one step further: control it from your phone
Fit the BTCO GSM Module to any BTCO starter and it becomes a mobile starter. Switch the motor ON or OFF from the free BTCO Starters app or by SMS, and get an alert on your phone when the power goes or comes back, or when the starter trips on dry run or overload.
Dry run, overload and single phasing are the most common reasons a motor burns. Read why submersible motors keep burning, and how to stop it.
Frequently asked questions
What is an automatic starter for a submersible pump?
It is a starter that runs the pump without anyone standing next to it. It starts the motor by itself when power comes back, and stops it by itself when something goes wrong, such as dry run, overload or a missing phase, before the motor burns.
Does an automatic starter switch the motor on after a power cut?
Yes. When power comes back, a BTCO starter waits for the auto start delay you have set and then starts the motor on its own. On the DOL-03 you can set this delay from 5 to 240 seconds.
How is a fully automatic starter different from an auto switch or a single phasing preventer?
An auto switch only turns the motor on when power returns, and a single phasing preventer only trips the motor when a phase is missing. A BTCO fully automatic starter does both, and also protects against dry run, overload, earth faults and cable faults, restarts after a dry run trip and shows why it stopped.
Which automatic starter do I need for a 5 HP or 7.5 HP motor?
For a 3 phase single cable motor up to 10 HP, the DOL-03 (3–7.5 HP or 7.5–10 HP variant). For a double cable motor from 7.5 HP, the FASD-03 star delta starter. For a single phase motor up to 5 HP, the FASP-01. If your village gets only juice line or 2 phase power, a Combined starter. Tell us your motor HP and we will confirm.
Can I make my existing starter automatic?
Yes, if it is a 3 phase DOL or star delta starter. Fit the BTCO MPAU: it adds auto start and motor protection to the starter you already have, for motors up to 30 HP.
Can an automatic starter run the motor on a timer?
Yes. The DOL-03 and FASD-03 come in a timer + WLC variant with normal, cyclic and RTC timers, and the Single Phase Domestic starter has timers built in. With the BTCO GSM Module fitted, you can also set timers in the BTCO Starters app on any BTCO starter.
Does an automatic starter work on juice line or 2 phase power?
The BTCO Combined starters do. The Combined DOL runs 3 phase motors up to 10 HP on juice line, 2 phase or 3 phase, and the Combined Star Delta runs motors up to 25 HP on 2 phase or 3 phase, and on juice line up to 10 HP.
Get the right automatic starter for your motor
Call or WhatsApp us with your motor’s HP, single or double cable, and your power supply, or visit your nearest BTCO Starters dealer. More answers in our motor starter FAQ.
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