Thread: Some VSD questions

Hi Joe, Chris,

Joe, it's a multi part series, this one is just part 1... might be easier/cheaper to buy the magazine for the subsequent parts of the series..

The more I think about it the more I like it..

First thought, is that it will be more expensive to build than to buy a Huanyang. But on the plus side it's a fully documented design with circuits and software, so the potential to maintain it into the future is much better than the Huanyang.

The build quality of the Huanyang is a bit ordinary, this at least gives you the opportunity to raise the level of the build quality

They have used the STGIPS20K60 module for the output stages, and I see they are readily available from Mouser for about $25-$30 each, so I'd be thinking of putting a few of them aside Mouser Electronics - Electronic Component Distributor STGIPS#20K60

The idea being that the most likely part to fail is the output module, and being an STMicroelectronics module most likely means only one source of supply..

The processor is a Pic32, which is a family I'm pretty well aquainted with, so that's in the comfort zone.. on the other hand they don't say if the code will be available for download ( or if they did I missed it..) Sometime with these sort of projects they sell the preprogrammed chips, which means changing the code becomes a reverse engineering exercise, or a rewrite from scratch..

Conclusion is I will definately be building one or maybe more. It looks like a well engineered and well thought out project.

Silicon Chip VFD

Regards
Ray

That sound good Ray. From the SC website it came out two days ago - so I should be able to get it in Bendigo on Saturday. I'll keep my eyes open for the subsequent installments and get them too.
Your appraisal of the design is encouraging. I've built a few SC projects over the years successfully despite my relative lack of expertise in elecronics.
Joe

Ray is this likely to be offered in a kit? Any idea of cost?

I have bought all Sew-Eurodrive VFDs and they were cheap. One was brand new, latest model, and under A$100 landed. I like them but guess the older versions I use don't have the features of the latest. It would be interesting to see how much building one would cost.

Pete

The article says it should cost under $200.

Hi Chris,

I'd expect that $200 is about right for a full kit, but having something that is documented and maintainable is worth a bit extra. If you only repair it just the once, then you've probably saved the commercial replacement cost right there..

Pete, I don't think there is any mention of plans to offer it as a kit, but based on previous SC projects that's their normal procedure.. Jaycar perhaps.

Regards
Ray

Thanks Ray, no desire to build one myself, will stick with my Sews, but was just curious how much a roll-it-yourself job would cost. Every so often I'll pick up an electronics magazine and reminisce, but to be perfectly honest don't keep up to date with what's going on in the electronics hobby world, it's not like the old days. You'd think it both being my trade and then having spent 7 years at college studying the field I could show a bit of enthusiasm

A past interest was high-end audio, so every now and then I have a rush of blood to my head and build something in that field*, tick the box, and the Weller gets shoved back in its drawer

Pete

*The last thing was a headphone amp, complete with Sennheiser HD650s. Proved the point, and there the thing sits, still to be permanently wired into its case

The big attraction for me with the SC DIY VFD (3 acronyms in a row!) is that it also runs single-phase motors (provided they don't have a centrifugal start switch). I've got 3 pool pumps, and my power bills are ruinous. Hopefully these VFDs will pay for themselves within a few years.

the mention of pool pumps reminded me of this device, which cuts down the cost of running the pumps by up to 80%
The Story

Lather,
I believe the SC VFD is does the same thing as the device you linked to, but at a fraction of the cost.

There isnt much info on the site. No " independent tests results" that I can find to "not believe". Nothing about how it does what it does. Not even the patent number.
There are lots of "up to"s though and some 2+year old testimonals.
Unless its PF correction(which isnt an issue as far as I know for dosmestic supply), If it only slows the pump down, why not just fit a smaller pump? Maybe a 2hp pump running at 50% makes less noise than a 1hp pump running at 100%?

Stuart

edit There seems to be a little more info on there installation page and the pdf guide

Stu,
the way the SC article describes it, most pool pump are oversized to allow them to overcome friction in the seals when they are cold and to purge any air from the lines.

The SC VFD has a "pool pump mode" that runs at full power for 30 seconds then drops to a level set by the user (70% recommended).

I don't believe the unit lather linked is in any way dodgy, but I doubt their claim of 80% energy savings unless your pump was massively oversized.

Chris

Originally Posted by RayG

Hi Joe, Chris,

Joe, it's a multi part series, this one is just part 1... might be easier/cheaper to buy the magazine for the subsequent parts of the series..

The more I think about it the more I like it..

First thought, is that it will be more expensive to build than to buy a Huanyang. But on the plus side it's a fully documented design with circuits and software, so the potential to maintain it into the future is much better than the Huanyang.

The build quality of the Huanyang is a bit ordinary, this at least gives you the opportunity to raise the level of the build quality

They have used the STGIPS20K60 module for the output stages, and I see they are readily available from Mouser for about $25-$30 each, so I'd be thinking of putting a few of them aside Mouser Electronics - Electronic Component Distributor STGIPS#20K60

The idea being that the most likely part to fail is the output module, and being an STMicroelectronics module most likely means only one source of supply..

The processor is a Pic32, which is a family I'm pretty well aquainted with, so that's in the comfort zone.. on the other hand they don't say if the code will be available for download ( or if they did I missed it..) Sometime with these sort of projects they sell the preprogrammed chips, which means changing the code becomes a reverse engineering exercise, or a rewrite from scratch..

Conclusion is I will definately be building one or maybe more. It looks like a well engineered and well thought out project.

Silicon Chip VFD

Regards
Ray

I asked SC, they will not be distributing the source code, so modifying the software will be impossible. A real shame as the hardware looks good. How can you learn about electronics if all the brains is hidden away in a little chip where you cannot play with it?

Originally Posted by bloodandsawdust

I asked SC, they will not be distributing the source code, so modifying the software will be impossible. A real shame as the hardware looks good. How can you learn about electronics if all the brains is hidden away in a little chip where you cannot play with it?

Not completely surprised by that, I guess whoever who wrote the software is expecting to get some re-imbursement by selling the pre-programmed chips.

I'm still keen to build one, and maybe after getting familiar with the hardware it might make a good open-source project to re-write the software... I wouldn't expect it to be a trivial exercise however..

Regards
Ray

Originally Posted by RayG

Conclusion is I will definately be building one or maybe more. It looks like a well engineered and well thought out project.

Silicon Chip VFD

Regards
Ray

Unlike the old Dick Smith kits from the 1980's , they were mostly crap that were almost impossible to build and get to work as the designers intended .

That guy made millions of dollars importing and selling Japanese and other Asian electronics , he now runs around saying we need to buy Australian made .... rather hypocrytical I'd say