For a long time, I have been using a Jinasena N110T/1 water pump. The specs are as follows:

  • 1" x 1"
  • H max 80ft
  • 1000 gph @ 42ft 0.75 HP
  • 220-240V
  • 0.56KWh

I have heard from many places and other questions on this site that starting the water pump (it is about 30 yrs. old) will take about 3x the current it takes for running. I have also heard with that with something called a "Motor Starter" it can allow me to start the motor on an inverter that is a Bestek 1KW. I found a Motor Starter on eBay AC Contactor Motor Starter Relay CJX2-1801 3 POLE+1NC 220V/380V 18A COIL 4/7.5KW.

I am new to this Motor Starter concept and am wondering whether this will suit my purpose and how it works.

I appreciate any and all replies.

Thanks in advance.

PS:- I hope I have posted this in the right place. I would appreciate it if anyone could inform me if that is the case.

  • Not clear on what you're hoping to do. Are you trying to run this pump at three times its rated power in order to increase the volume or pressure? Why would the motor relay help you run this from an inverter? Mar 14, 2016 at 15:39
  • @DanielGriscom 1. It's quite clear. Run the motor from the inverter. But without the model or starting current rating of the inverter, one can't answer that it will or won't work. 2. No. The starting current is up to 7 times higher than the running current. 3. That relay won't. It's just a relay. But a soft starter might.
    – Dan D.
    Mar 14, 2016 at 16:12
  • Edited question to make it clear that starting current is the concern. Mar 14, 2016 at 16:30
  • Sorry for the late reply. I am only planning to use this inverter only when the power goes out (we've had lots of power failures recently). The rated peak for the inverter is 1400w. Thanks for explaining about the motor starter. Sorry, but I can't get the starting current as it is wired directly to somewhere, will try to test when I have time. Can I run the motor with the 1400w peak, as I have heard that the starting current for the motor I have is about 2-3x rated current, but not sure about it. Will do this as soon as I am able to. Thanks for the comments and the answer.
    – Sanoo
    Mar 15, 2016 at 14:27

1 Answer 1


The link is just a standard 4 pole relay it will not help other being an on off device. A motor inverter is a device that takes line voltage and adjust the voltage and frequency. With a very old motors it is not advisable to use inverters or soft starts because of the harmonics generated will cause the bearings to be destroyed in a matter of months. Pump motors don't do well with soft starts because they slowly ramp the frequency or pulse full power then pause pulse pause until at full speed then a internal contactor locks the line to the load. With each delay in pulses the pump slows down and causes more heating. Bearing failure was a huge problem in the early days of VFD’s (variable frequency drives). E series high efficency motors solves that problem. Here is a powerflex 40 From e-bay so you understand what a motor inverter or VFD is. With a VFD a relay or contactor is not needed. The Bestek 1KW may not be able to run the motor as these types of inverters usually will not push a pure inductive load like a motor.

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