Most motors give warning signs before they burn: the voltage keeps dropping, one phase draws more current than the others, the amps creep up as the pump wears. With an old starter you never see these signs. A digital starter shows them to you on its display, and a BTCO digital starter acts on them by itself, switching the motor off before it burns and telling you why. Here is what the display shows and how to read it.
What is a digital starter?
A digital starter has a digital display and a microcontroller instead of only switches, a relay and analog meters. It measures the supply voltage and the motor current all the time, shows them on the display, and uses them to protect the motor. In every BTCO starter this is the MPAU unit, which also starts the motor automatically when power returns.
What the display shows
- Volts on all three phases at once: RY, YB and BR. BTCO 3 phase starters are made for a 380–415 V supply.
- Amps on all three phases at once: R, Y and B, the current your motor is drawing right now.
- R, Y and B phase lights, so you see a missing phase at a glance.
- Your settings: auto start delay, dry restart time, overload trip amps, star delta changeover time, and timers and water level control on the timer + WLC variants.
- The reason for every trip, in words, such as Dry Run Trip or Mains Problem.
How to read the volts and amps
- Volts: the three readings should be close to each other and inside the normal supply range. If they keep dropping in the evening, or one phase is much lower, your line has a voltage problem. See how voltage fluctuation burns motors.
- Amps: compare them with the rated current on your motor’s nameplate. The three phases should be close to each other and not above the rated current.
- Amps higher than normal: the motor is working too hard, from a jammed pump, worn bearings or low voltage. See overload protection.
- Amps lower than normal: the pump may be running short of water. See dry run protection.
- One phase very different from the others: an imbalance or a missing phase. See single phasing protection.
You don’t have to watch the display all day. A BTCO starter reads these values all the time and trips the motor by itself when they go out of the safe range. The 3 phase and Combined starters even learn your motor’s healthy amps the first time they are connected.
What the trip messages mean
| Message | What it means |
|---|---|
| Dry Run Trip | The pump ran without water. The starter restarts after the dry restart time. Watch the video |
| Overload Trip | The motor drew more current than the overload trip amps. Watch the video |
| Mains Problem | A problem on the supply: a missing phase, a blown fuse or a cut wire. Watch the video |
| Ground/Imbalance | Current leaking to earth, or one phase drawing much more than the others. Watch the video |
| Check Cable/Kit | A fault or leakage in the cable to the motor or in the winding. Watch the video |
| Instrument Fault | The starter has found a problem inside the unit itself. Watch the video |
Every message has a video in English, Kannada and Telugu on our videos page. Knowing the reason saves you a wasted trip: Mains Problem means check the line and fuses, Check Cable/Kit means check the cable joint, not the starter.
Digital starter or analog meters?
Many older panels have an analog voltmeter and ammeter, often with a selector switch to check one phase at a time. They show a reading, but they don’t act on it. A BTCO digital starter shows all three volts and all three amps together, uses those readings to protect the motor from dry run, single phasing, overload and voltage fluctuation, and tells you in words why it stopped.
See the display on your phone
Fit the BTCO GSM Module and the same volts and amps appear in the free BTCO Starters app. You can check your motor from home, switch it ON or OFF, and get an alert with the reason when it trips.
BTCO digital starters
| Your motor | BTCO digital starter |
|---|---|
| 3 phase, single cable, 3–10 HP | DOL-03 fully automatic DOL starter |
| 3 phase, double cable, 7.5–30 HP | FASD-03 fully automatic star delta starter |
| 3 phase on juice line, 2 phase or 3 phase, 3–10 HP | DOL-2/3 Combined juice starter |
| 3 phase, double cable, 7.5–25 HP, on 2 phase or 3 phase | FASD-2/3 Combined star delta starter |
| Single phase, 2–5 HP | FASP-01 Single Phase starter (volts and amps display) |
| You already have a 3 phase DOL or star delta starter | MPAU: makes your starter digital |
See every protection your motor needs in our submersible motor protection guide, and read why submersible motors keep burning, and how to stop it. Also useful: what a fully automatic starter does and starters with timers.
Frequently asked questions
What is a digital starter for a submersible pump?
It is a starter with a digital display that shows the supply volts and the motor amps, and a microcontroller that protects the motor. A BTCO digital starter also starts the motor automatically and shows the reason whenever it trips.
What does the display on a BTCO starter show?
The volts between each pair of phases (RY, YB and BR), the current on each phase (R, Y and B), the settings you make, and a message telling you why it tripped, such as Dry Run Trip or Overload Trip.
What amps should my motor show?
Compare the amps on the display with the rated current on your motor’s nameplate. When the motor runs normally, the three phases should be close to each other and not above the rated current. Much higher amps point to overload or a voltage problem; much lower amps can mean the pump is running dry.
Is a digital starter better than one with analog meters?
A digital starter shows all three volts and all three amps at once and tells you why it tripped. It also uses those readings to protect the motor automatically, for example from dry run, single phasing and overload.
What does Instrument Fault mean on a BTCO starter?
The starter checks its own health. Instrument Fault means it has found a problem inside the unit itself. Watch our Instrument Fault video, or call your BTCO dealer for service.
Can I see the volts and amps on my phone?
Yes, with the BTCO GSM Module fitted. The free BTCO Starters app shows the same volts and amps as the display, and alerts you when the starter trips.
Get a BTCO digital starter for your motor
Call or WhatsApp us with your motor’s HP, single or double cable, and your power supply, and we’ll tell you which BTCO digital starter fits. Compare every model on our submersible pump starters page, or visit your nearest BTCO Starters dealer. More answers in our motor starter FAQ.
More videos on our videos page. Follow BTCO Starters on YouTube, Instagram and Facebook.
