Can I use a 1KW inverter along with a motor starter to power a water pump?


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...

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By Stefan Fassbinder (DKI)

An electric motor and an electricity generator are basically the same.

By principle, any electric motor can also generate electricity. Electric drives are way ahead of combustion engines, since, unfortunately, a car engine which sucks up exhaust fumes during braking and downhill rides and converts them into fuel and fresh air is still pending. The electric motor can deliver this, although during its first century of existence, its use has largely been hampered by two basic drawbacks:

An electric motor has no accelerator pedal. A socket has no sort of “water tap”.

When an electric motor is running, it generates a voltage with a polarity opposite to the feeding voltage.

Therefore the current is excessively high at the first instance of switching on when the motor is not yet running. For big motors precautions have to be taken not to damage it or blow any fuses. As the motor speeds up, this induced voltage increases. In...

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Re: Using a generator to power a washing machine

I am a big believer in basic measurements... So, measuring the kWH total each time you run time it--And the amount of fuel used. Get something like kWH/Gallons (or liter) of fuel used...

More or less, you are pretty efficient if you are getting 4kWH per gallon (or ~1kW per liter)... And not doing too well if less than 2kWH per gallon (or ~0.5kWH per liter).

For example, the inexpensive generator that Chris Olson likes (the Champion 46539) is a 3.5kW unit with a 3.8 gallon gas tank that will (per specs) run about 12 hours at 1/2 load, or:

3.5 kW * 0.50 loading * 12 hours * 1/3.8 gallons = 5.5 kWHh per gallon

That is not too bad... The non-inverter generators tend to be more efficient at >50% load and the inverter generators tend to be more efficient (than non-inverter types) at less than 50% load--But that still does not mean that inverter generators are "that" fuel efficient--They just tend...

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Hello! I’m attempting to run a 240 V well pump on a Xantrex SW4048 inverter via a 120/240 V, 4 KVA step-up transformer. The pump will start and run if no other load is present, but with even a few lights on, the inverter overloads and trips out. I called the pump motor manufacturer and they confirmed that the two-wire, 1 hp pump pulls 48 amps at 240 V for about 0.2 seconds during startup. However, since the inverter is supplying 120 V, the actual current the inverter has to supply is 96 amps! The surge ratings for the Xantrex SW4048 from the literature I have says 110 amps for 0.01 second, 77 amps for 0.1 second, and 73 amps (resistive load) for 5 seconds.

I also reviewed the manual for our newly installed submersible well pump (Goulds), and they have a section on sizing a generator to run the pump. For a 1 hp, three-wire pump, they recommend a minimum of 4,000 watts. For a two-wire pump, they recommend increasing the generator size by 50 percent.

I’m not sure why the...

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Power inverters bought at the store are limited capacity. No matter what the rating, you plug it into your cigarette lighter. The fuse for that lighter socket is rated for 10 amps. At 12v, that's 120w. Even through the converter, it's still 120w out. Not enough to power more than small devices.

Even if you hooked right up to the alternator, the maximum output is 50 (maybe 60) amps. So you've got 600 watts. Again, not much. And continuously running your car's alternator under full load is going to wear it out very quickly.

If you don't have power service for a home, then you need an electric generator. Gas powered ones are actually the cheapest to buy and to operate. Make sure it's rated high enough in kVA (watts, basically) to handle all the appliances in your home.

For building your own inverter, the cheapest ones just use a chip that generates a square wave. That square wave is then run through a transformer to step it up to the voltage you want. It's fine for...

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When heavy motor systems or high current motors are involved, initial switch ON current surge often becomes an issue. This surge tends to inflict huge sparking across the pump relay contacts causing corrosion and reduction in its life due to stress, and wear and tear.

The sparking of the motor not only causes relay contact issues, but also affects surrounding electronic circuits, causing them to hang or get disturbed due to large amount of RF interference generated during motor switch ON.

However safeguarding the costly motor relay becomes the main issue with such situations. Though there are many mechanical contactors available for controlling motor stress, these system are not efficient and are ineffective against the RF emissions.

The simple electronic circuit presented below hopefully is able to eliminate all issues concerned with heavy motor switch ON surge generation and relay contact protection.

The figure shows a simple dimmer switch...

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An inverter sized by these minimum guidelines will dip its voltage during the starting surge. This is not harmful, but it will cause lights to dim. Fluorescent bulbs may blink off, and computers are likely to crash. To eliminate voltage dips, oversize the inverter by an additional 50% minimum plus the watts capacity required to handle other household loads at the same time.

Minimum inverter sizing is based on field experience with Xantrax inverters, allowing ~25% voltage drop during startup. To eliminate noticeable voltage dip, add 50% to the minimum size. Other brands of inverters differ in their surge capacity relative to continuous rating. Exact starting capacity is difficult to predict and inverter manufacturers are hesitant to specify it. Dankoff Solar welcomes your feedback and will publish more information as a result.

If a "modified sine wave" inverter is to be used and pump's control box is labeled "solid state", then it must be changed. Obtain a...

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Hi! SirAskalot,

I refer back to the pump manufacturer proposal, the recommended electrical connection is DOL and Star-delta starting. The electrical engineer proposed the motor starters shall be DOL type.

"Where Star-delta or Autotransformer Starters are used with Closed Transition type and the maximum transient current surge changing from one stage to another must not exceed 3 x motor Full Load Current (FLC)."

With both pump and motor technical specifications and the above proposal, do u guys think is it workable?

Let's say if Star-delta is used, how much voltage drop to drive the initial torque? There are 4 pumps in operation. Can this starter design start a pump at a time or 2?

Please impart me any input to rectify any potential problem. During the meeting, the contractor's engineer failed to draw a conclusion. They simply said they couldn't drive any of the 4 operating pumps.


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The electric problems of a 300kW induction motor start arise from the high inrush current, especially for the network supply, even with a star-delta starter. But there are also hydraulic problems to consider: they depend on the actual pipe/valve configurations used to smooth the variation of flow rate during start up and (very importantly) the shut down operation.

The use of an auto-transformer (usually with three or four steps) is an alternative; however its cost is relatively high and leads to the preference of a thyristor soft starter. Water pumping is usually compatible with the use of "soft starters" which are relatively cheap.

The best technical solution appears to be the use of inverter drives (with variable frequency and voltage). Although being more expensive they can be especially efficient for flow regulation where this is an objective.

As a rough conclusion I would say:

- soft-starter if it is intended just for a smooth start and flow...

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Efficient Carbon |3


The project intends to build a low cost Concentrated Solar powered pump to helpfarmers get reliable, inexpensive and clean power when they need the most. Eventhough there are multiple systems available currently, they range at around1.5Lakhs INR per HP. We are looking at reducing it to approximately Rs. 50,000 -60,000 INR per HP through technical innovations.Striling engine is the heart of the system that generates mechanical work fromheat input. Fresnel lens is used to trap the Solar light on to the point focused heatcap of engine. Striling engine shaft output is connected to the alternator which

converts mechanical output of Striling Engine to Electricity. Alternator’s electrical

output is connected to motor starter which supplies the required power formotor and pump...

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Energy saving using inverter is always vary application to application. Following points you need to consider before using frequency inverters for energy saving.

How much process flow and pressure requirement through AC motors Existing control methodology like control valve in pumps, Damper or guide vane for Fans & Blowers etc. and position of the valve or dampers If you have process flow and pressure data and pump or fan design data, you can calculate energy saving using affinity law Loading and Unloading cycle for compressor application. If the unloading time is higher for compressor application, you will get better energy saving Using affinity law, you can calculate the energy saving with consideration of frequency inverter losses. With this you can calculate the Pay back of frequency inverters.

Simply put, an


can save energy COMPARED to OTHER means of VARYING flow and/or pressure in centrifugal machines, like pumps and fans....

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