Report KD 747 about 30-pole generator available

[Adriaan Kragten]

Report KD 747 can be copied for free from my website: https://www.kdwindturbines.nl at the menu KD-reports. The title of this report is: "Ideas about a 30-pole, 3-phase permanent magnet generator using the housing and winding of a 6-pole asynchronous motor frame size 112M. The armature has 30 mechanical poles and the stator has 36 poles resulting in 180 preference positions per revolution. This makes that the generator will have a rather low peak on the cogging torque. As the armature has 6 magnetic poles, it can be combined with the original 3-phase motor winding.

At this moment I can't add a picture of the generator as attachment. So if you want to see it you have to go to the report.

[Adriaan Kragten]

A new chapter 6 has been added to report KD 747. The title of this chapter is: "Using a 48-pole armature and a 12-pole, 3-phase, 2-layers winding".

[Adriaan Kragten]

The chapter about the 48-pole generator is cancelled and replaced by a new chapter 6 with the title: "Using a real 30-pole armature and a 3-phase, 1-layer winding".

[Adriaan Kragten]

Report KD 747 has been reviewed. The magnets size 40 * 10 * 4 mm as used for the generator frame size 112 have been replaced by magnets size 40 * 10 * 5 mm because the original magnets were no longer at stock at Enes Magnets. A new chapter 7 has been added to report KD 747. The title of the chapter is: "Ideas about a 42-pole generator made from a 7.5 kW, 6-pole motor frame size 160". The armature of this generator makes use of 84 magnets size 40 * 10 * 10 mm. The magnet costs are about € 166 which is very low for a PM-generator of this size. The original winding and the original motor shaft can be used. This shaft has a diameter of 42 mm and a length of 110 mm. It might be possible to use this generator for the VIRYA-5B3 which is described in report KD 710.

[joestue]

Report KD 747 has been reviewed. The magnets size 40 * 10 * 4 mm as used for the generator frame size 112 have been replaced by magnets size 40 * 10 * 5 mm because the original magnets were no longer at stock at Enes Magnets. A new chapter 7 has been added to report KD 747. The title of the chapter is: "Ideas about a 42-pole generator made from a 7.5 kW, 6-pole motor frame size 160". The armature of this generator makes use of 84 magnets size 40 * 10 * 10 mm. The magnet costs are about € 166 which is very low for a PM-generator of this size. The original winding and the original motor shaft can be used. This shaft has a diameter of 42 mm and a length of 110 mm. It might be possible to use this generator for the VIRYA-5B3 which is described in report KD 710.

i would be concerned about anything that's going to go over 200hz in real life. adequate margin has to be ensured so that you can stop the turbine.

I still have my 30 pole machine using 50x6.25x3mm magnets (actually 2" by 1/4" by 1/8). originally it was a 6 pole 1/3rd hp induction motor,

it produces 120vac 4 amps at 400hz and 1750 rpm pretty efficiently, but you can short circuit the windings, and only produce 9 amps at that frequency, only drawing maybe 100-120 watts of shaft power. 

i have a bigger lathe i could test it in.. i wonder if capacitors in series with the generator would enable short circuiting the motor to actually stop a turbine, or if it needs a critical resistance in series to match the inductance.

[Adriaan Kragten]

The poles mentioned in the title of report KD 747 are the number of mechanical armature poles. The number of magnetic poles of armature and stator is six. The stator has 36 slots and so 36 mechanical poles. So one magnetic armature pole has five mechanical poles and one magnetic stator pole has six mechanical poles. This difference in mechanical pole numbers reduces the peak on the cogging torque. The original 6-pole, 3-phase winding is used and so you get a frequency of 50 Hz at a rotational speed of 1000 rpm. The frequency for use as windturbine generator is much lower. A real 30-pole generator, so with 30 magnetic armature poles, is described in chapter 6 of KD 747. For this version, the frequency will be 50 Hz at 200 rpm.