Controller Part 2

(as you can see I don't like dealing with insurance companies, hence the lack of Insurance Part 2 lol)

My Digikey order arrived today! I absolutely love 1 day shipping. Going to post some pics of the unboxing; wow are those diodes HUGE! Also on the block: homemade wire terminals out of copper pipe.

Well if anyone asks what $220 of electronics buys, the answer is.. not much.

To be fair, the roll of Kapton tape to the left is $25 or so, which would be another nicely sized pile.

Without further ado, here is the main event:

*insert crowd oohs and aahs here*

Three things surprised me here.

1. Those diodes are MASSIVE! Probably twice the size I expected.

2. Those transistors are TINY! About half the size I expected. I mean, look how small the contacts are!! And they can carry 190A?!? (Remember, that spec from the datasheet, I_D_max at 25°C is kinda bogus, that is with some super heatsinking to keep the case at 25° while at full load.)

3. Those film capacitors (red) are very very light. I dropped one (I have been dropping everything today) and I immediately lost it. It turns out it bounced and ended up about eight feet from where I dropped it straight down. Weird. Also the red carpet and low lighting didn't help in finding it.

So here are the wire terminals I made from some copper pipe; the last of which is at the top of the pic.

These four will connect the starter motor cables and the battery cables to the buss bars.

Here is the starter motor again, with the fifth terminal attached. What you see is called the solenoid; it serves two purposes. One is to be an electrical relay for the starter (which can pull way more current than your ignition switch could ever dream of handling) and the other is to drive the starter's gear against the flywheel of your engine.

On the left you will see the gear recessed into the starter housing, this is the idle position. When starting, the gear is pushed out by the solenoid and the starter turns the flywheel. Once your car starts, the gear is forced back into the housing, not by the solenoid, but by the flywheel which is now spinning faster than the starter. If this didn't happen, the starter motor would be overrevved and probably explode from centrifugal force.

Anyways the main point of the pic was actually to show the mounting of the last terminal, the ground of the starter motor. Cars are designed such that the positive side of the battery is routed by cables to their destinations, while the negative side is connected to the frame of the car. The bolt hole I am using is actually how the starter is mounted to the engine block. Works perfect!

This kind of stuff I like to scrounge from junk we have lying around, which sure brings the cost down. Terminals like the ones I show here are about $6 apiece from Canadian Tire, so I made $36 of parts from about a foot of scrap copper pipe, worth about $2 if you had to buy it. Plus about 3 hours of labour, including cleaning mouse nest and droppings from the drill press. God I hate those buggers. If you had a clean shop you could do it in 30 minutes, tops.

Anyways, enough writing, time to play!

First step is to hook up my mosfet drivers, throw it on the scope and see what kind of risetime I can get :)