Increase the lifetime of the Inverter

Also make shure about adequate ventilation around inverter, insects and dust can also reduce life time and avoid running inverter at max capacity, Max capacity means more amps going through components thus more heat that will bake components over time and cause failure

Inverterman said:

Also make shure about adequate ventilation around inverter, insects and dust can also reduce life time and avoid running inverter at max capacity, Max capacity means more amps going through components thus more heat that will bake components over time and cause failure

Click to expand...

You are not answered the question

PA3040 said:

You are not answered the question

Click to expand...

On startup you won't pull as mutch amps through inverter because the torque is handled by the grid thus less thermal energy need to be dissipated by internal components, which will lead to longer life.The answer I gave was general tips for increasing inverter life

By "water motor" i believe you mean "pump".

So it sounds like you are worried about high start up current in the pump motor, and so you want to start it up on the grid, then switch over to your inverter when the pump is fully up and running.

...The thing is without knowing the pump's startup overcurrent, i cannot answer the question. If its just a small inrush current then it wouldnt bother the inverter.

Some pumps have internal current limiting in them anyway...so the inrush wouldnt be a problem in that case...ie not a problem for the inverter.

If it was a BLDC pump than i'd say you could do that kind of switchover, but with other kinds of pump motors, you would be breaking an inductive current when you switch out the pump from the grid, and this would cause arcing to the contactor....which would mean its lifetime may be quite short.

@ cupoftea - can you please show a pump that connects to the mains that has internal current limiting as you suggest ?

@ cupoftea - can you please show a pump that connects to the mains that has internal current limiting as you suggest ?

Click to expand...

Thanks, yes a BLDC pump...with inverter........the inverter supplies the pump...and the inverter leg currents all have current limiting....it connects to the mains...the mains is then rectified, theres an isolation stage...then the DC bus for the inverter, which feeds the pump.

so grid to pump to start up
contactor to remove grid and connect solar inverter

potential problems
removing power from inductive load (pump motor) can cause high voltage spikes
connecting ac from inverter to rotating motor may cause issues if the phase difference
between the inverter output and where the motor is in its cycle are not synchronized
(or at least close)

it may not be necessary to add the contactor
the inverter may be able to handle pump the inrush current

what is the inrush current, and for how long, of the pump?
what is the maximum normal capability of the inverter?
what is the short term overload capability of the inverter?

Looks like OP not back yet...anyway, OP probably gets the idea that they can indeed possibly reduce sress on the inverter by doing the "switchover scheme".....however, it would help to have a decent snubber across the contactor in order to handle the inevitable momentary breaking of inductive current at switchover time.....and even a good contactor will bounce a little.....making and breaking the inductive current, sparking like mad, and getting cumulatively damaged....you cant even reduce contactor wear by switching at the zero current point...because the bouncing will extend outside this....but what about a solid state "contactor"...that wont bounce...this could be switched at the zero current point.

Of course, the OP may have gone off to find a current limited pump...such as an inrush current limited BLDC pump.

Is there really no kind of non-BLDC pump, powered directly from the mains, that doesnt have the large inrush problem that OP refers to?

cupoftea said:

By "water motor" i believe you mean "pump".

Click to expand...

Yes Water Pump

Click to expand...

cupoftea said:

...The thing is without knowing the pump's startup overcurrent, i cannot answer the question. If its just a small inrush current then it wouldnt bother the inverter.

Click to expand...

Following the motor spec available

Type Domestic Pumps
Motor (HP) 0.75
Total Head 83ft
Suction Lift 25 ft
Pipe Dimension 1" X 1"
Capacity (gln/h) 1650
Phase Single
Operating Voltage 230v

Click to expand...

cupoftea said:

Thanks for the reply

Click to expand...

wwfeldman said:

what is the inrush current, and for how long, of the pump?

Click to expand...

Available information the pump motor

Click to expand...

Type Domestic Pumps
Motor (HP) 0.75
Total Head 83ft
Suction Lift 25 ft
Pipe Dimension 1" X 1"
Capacity (gln/h) 1650
Phase Single
Operating Voltage 230v

wwfeldman said:

what is the maximum normal capability of the inverter?

Click to expand...

It is 5Kv Inverter .... the data sheet is attached

wwfeldman said:

what is the short term overload capability of the inverter?

Click to expand...

Surge Rating 10Kv.......datasheet is attached
Thanks for the reply