Wednesday, 13 August 2014

Gen project- single phase transformer

Before we became too involved in re-wiring the SmartDrive unit we found a small transformer. This gave us the idea that we can stick with our 12V phase voltage output and simply transform up to 24V.
We want 24V rather than 12V because we have a 24Vdc inverter.

Our transformer is a multi-tap type and has various voltage inputs and outputs depending on what way you hook it up.

We connected the red phase (only a single phase transformer) of our generator up to the 22V primary. 22V? I thought we wanted pretty much that? Yes.. but that happens to be the smallest primary winding available.. but that's not a concern because:
The lowest secondary winding of this transformer has an output voltage of 200V, now we only want just over a tenth of that, keep in mind 200V will only be produced at full noise and we want some flexibility with this voltage.

So what we achieved was, just with spinning the unit with our hand, a 37V output at approx. 100rpm.
This means that at higher speeds we can easily achieve higher voltages or, when we connect a load and have volt drop under load, we can spin the unit a bit more to keep our 24V output.

The next stage we will be looking at is getting two more transformers or a 3phase transformer so we can utilise all 3 phases and create a diode bridge rectifier to get our DC flowing.

Gen project- our SmartDrive

We are starting with a smart-drive unit already configured for around a 0-40Vac output depending on the speed.
We know this after finding this website:

We spun our unit up with a battery drill to see what sort of voltage we could achieve. We measured 24Vac at 400rpm. And even more at higher speeds.
It was good to see we were getting a usable voltage out of it, but the speed needed to generate that is  too high. Its unlikely that we will be able so get our pelton wheel spinning that fast.
Our plan now is to reconfigure the windings on the stator to have a higher output at lower RPM

Tuesday, 12 August 2014

Gen project - beginnings

As a class we are undertaking a joint generation project. The goal- run our classroom on the power we generate and feed the grid with the excess.

The types of generators we are trying to create are: hydro, wind, solar and fossil fuels. All will be joint at a common bus to charge batteries and run our inverters.

As a team we have Hydro

We will post our progress in this blog and the research we do to get our generator generating.

This is what we are starting off with, the leftovers of last years attempt.
We have a Pelton wheel turbine, a bath and pump to simulate river flow/ creek flow/ water head... whatever.
Now we are not trying to create some sort of perpetual energy machine, we are not going to attempt to power our pump from the energy we generate. That simply won't work. The pump will be running off an external energy supply and is not counted as being part of our system, it is just there to get some water moving as we don't have access to a river.

We are using a Fisher and Paykel Smart-Drive washing
machine motor for our generator.

As it stands our set-up is not plug and play, previous attempts have found that when the generator is connected to a load, the water pump is not powerful enough to spin the Pelton wheel.

Throughout this generation project our team will publish updates on our progress to power our classroom and successfully construct a mini hydro generator.


Power Points

The Great New Zealand Power Stocktake 

youtube link

Photoelectric and Piezoelectric generation

youtube link

RCD and similar protective Devices