Author Topic: ac clipper max voltage question  (Read 236 times)

bennyspoon

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ac clipper max voltage question
« on: July 15, 2018, 02:50:56 AM »
Hi gang,

I recently aquired a q4 14 ac clipper that i am going to pair up with a 250v classic.

The sticker on the side of the unit and the sticker underneath the 3 phase input wires both state 250v max.

In the video MidNite Solar - Clipper/Classic Installation - Ricks on youtube the voltage of the unloaded turbine is shown to be in excess of 420 volts dc.

Basically my question is, before I wire my stator up, what is the max voltage that the clipper can see without damage?

Thanks,
Ben.


« Last Edit: July 16, 2018, 03:29:03 AM by bennyspoon »

FNG

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Re: ac clipper max voltage question
« Reply #1 on: July 15, 2018, 12:49:28 PM »
The clipper will not see greater than 250vdc as it clamps at or below the 250 volts, thus loading the turbine so it never open circuits. So its sort of chicken and egg in a way but the fact the clipper is powered from the turbine and pwms the resistors means it will never allow open circuit

boB

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Re: ac clipper max voltage question
« Reply #2 on: July 15, 2018, 07:20:40 PM »

I think that the capacitors are really the maximum voltage limit and I think those caps are 315 V DC rated with some room for surge for short term voltage.

I have seen as much as 350 VDC out of the Clipper momentarily.

FNG has a good point.  BUT what you might want to do is to reduce the clipper voltage set point to something low-ish to make sure it operates OK.

If you can, hook the turbine up during  lower wind speeds so it's not gusting big time.  Make sure the clipper board is going to power up.  The fans and power supply (turbine powered) will not come on until around 50V input.  There is a jumper you will want to check on the PCB for turbine powered.

Then adjust the trim-pot fail-safe to something around 250V or slightly less.  You can also drive the clipper from the Classic aux output and force it come on and clip.  You will want the Classic to trigger at a lower voltage than the Clipper fail-safe circuit for typical operation.

The rectifier and SSR are rated for 600V.

boB

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bennyspoon

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Re: ac clipper max voltage question
« Reply #3 on: July 19, 2018, 04:24:12 AM »
Thanks for the replies chaps.
Will test in lower wind or maybe via a hand drill first Bob.
Thanks for the tips.
Cheers,
Ben.