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Post up a thread for your EV. Progress pics, description and assorted alliteration
T1 Terry
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Post by T1 Terry »

Could a suitable plate be made to fit the rear end plate and holes drilled and tapped simliar to the front housing ones?

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Post by 4Springs »

T1 Terry wrote: Could a suitable plate be made to fit the rear end plate and holes drilled and tapped simliar to the front housing ones?

Not easily.
The rear end is a thin sheet metal cover over a plastic fan. Any such plate would need to attach to the four bolt holes that hold the cover on, but wouldn't want to cover up the ventilation holes around the side. I presume the fan sucks air in through a gap around the rotor shaft, and expels it out around the outside edge.

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Post by seligtype3 »

Intriguing. My 17R that arrived this morning has a solid rear with 4 mounting holes. Smaller BCD than the front but very usable. We must have different models?!
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Post by 4Springs »

seligtype3 wrote: Intriguing. My 17R that arrived this morning has a solid rear with 4 mounting holes. Smaller BCD than the front but very usable. We must have different models?!

Hmm...
Some photos are called for:

ImageImageImageImage

I'm still a bit confused about the "termal cut off" - which I think is what the white wires are. I noticed in the Kostov motor diagram that there is a little circuit diagram in the bottom right corner. This seems to show a "thermo switch" (one wire only) connected to the terminal A2. I'm not sure what the other parts of the diagram represent, but it sort of suggests that it is connected to the high voltage!
I emailed EVWorks (the supplier of the motor), and recieved this reply:

Hi Christopher

The two yellow wires that protrude from the motor casing appear to be connected to a thermal switch they are shown in the wiring diagram joined onto terminal A2 but as far as i can tell they are not connected to any of the high voltage terminals in side the motor and you could just as easily use a 12V supply to operate a light in the dash. We have not used these wires previously so i cant say for certain.
Cheers Tim
    

This wasn't terribly helpful. I might email Kostov and see what they say...

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Post by seligtype3 »

4Springs wrote:I'm not sure what the other parts of the diagram represent...


Weird diagram ey. Sparky friend and I examined it this morning and couldn't make much sense of it. Decided it was just a low voltage output if the thermistor trips. Send to a warning light in the dash or some other function as we see fit.

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Last edited by seligtype3 on Wed, 30 Mar 2011, 18:28, edited 1 time in total.
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Post by gholm »

I'd be interested to find out more about how it works and is wired up.

I have the Kostov R20, same wire and weird circuit diag on the spec sheet.
If a thermal overload does trip a circuit, what voltage gets switched?
By the look of it, coming from A2, it'd be the full pack voltage (in my case 144v).. which ain't too vehicle friendly for warning lights etc. You might need to run a separate relay.

Keep us posted on any further findings.

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Post by Johny »

Somebody grab a multi-meter and measure the damn thing!
Kostov can't possibly be that crazy - could they?

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Post by 4Springs »

I've measured them all right, they measure open circuit - to everything!
My guess is that the wires on the motor are switched together when the motor gets too hot, as suggested by evric. I'm thinking that these two wires are not the "thermo switch" on the diagram, since that only has one contact, and as Johny says, Kostov couldn't be that crazy... These wires are definately not connected to A2 when cold, but I'm not about to get out the oxy to see what happens when it gets hot!

I've emailed Kostov to see what they have to say...

Cheers,
Christopher.

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Post by evric »

It would be the thermo switch - I reckon they've just made a mistake with the drawing...
Has it got a tacho output? and a thermistor output? Some of the Kostov motors show these as well.
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Post by 4Springs »

Has it got a tacho output? and a thermistor output?
No, neither of those. I would have liked a tacho...

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Post by seligtype3 »

i'm sure the answer will turn up but in the meantime i'll be putting a temp probe into the motor case with a readout on in the dash to keep an eye on things.
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Post by Johny »

seligtype3 wrote: i'm sure the answer will turn up but in the meantime i'll be putting a temp probe into the motor case with a readout on in the dash to keep an eye on things.
Yes, I do not think that continuous temperature scale monitoring of the motor is over the top - good move. A warning is also good for "others" driving the car.

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Post by 4Springs »

Reply from Kostov:
Hello,

Indeed the switch closes when brushes/comm overheat so you can attach a light.
The sensor has no connection to the main voltage so should be safe :)

Here is the latest drawing where the normally open thermal cut off sensor is same like yours:
http://kostov-motors.com/files/producta ... 8_E62C.pdf


The motor in the drawing looks like yours seligtype3, showing the mounting points on both ends. The revision date on this drawing is 21/01/2011.

I've taken my motor, bell housing, flywheel etc. to an engineer in Perth to see what he can do about making them all fit together. This mechanical stuff is what I have the least experience with, so I'll take it to an expert and see what he produces.

The battery bloke rang yesterday as well - they are only a few weeks away from arriving. I'd better get cracking!


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Post by seligtype3 »

ah nice. good to know. thanks for sharing the email. i'm up to adapter plate too, getting an engineer friend to assist with the design and machining soon hopefully.
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Post by 4Springs »

Circuit Diagram

Be prepared to be amazed by my drawing skills:
Image

The two emergency stop switches are to be mounted on the battery boxes. #2 is under the bonnet, #1 is mounted inside the cab, at the front of the tray.
So in an emergency, first turn off the ignition key. If that doesn't work, turn around and thump the big red button behind you. I'll put it inbetween the two seats, so that it could also be reached by a passenger.

The Charge Relay is to make sure that you don't drive off while still plugged in. When 240VAC is present, the relay is open, which prevents the main contactor from being pulled in. After drawing this section, I realised that the Charge Relay and Inertia Switch should both be in the section above the main contactor. They should be on the contactor's positive side, so that a fault condition which earths the line (e.g. in a crash) doesn't pull the contactor in.

The Precharge Relay needs contacts that will stand high DC voltage, but not all that much current. I found a relay which is rated at 0.25A for 220VDC - $22 from RS Components. My precharge resistor is 2k, so at 144V this is 0.07A. To precharge, I turn the key to ACC for a couple of seconds before moving to ON. I wanted the relay because I wasn't happy with 144VDC hanging around when the key is turned off.

My DC/DC converter is on all the time. Not sure if this is a good idea, I'll need to measure how much current it uses when under no load. I could rig it to another set of contacts on the precharge relay, although I'd need a resistor to make sure it didn't draw more than the 0.25A relay rating.

Things that I've left off the diagram because they would just clutter it up:
Vacuum Pump
Battery Heaters & Water Pump
"Lights On" buzzer
Pot Box
BMS (such as it is)

Comments anyone? What have I forgotten? Does it look safe enough?
I've bought most of the components, but won't start wiring up until I get the motor and battery box positions sorted. So now is the time to make changes...

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Post by Richo »

Some DC-DC converters have a voltage free ON/OFF contacts.
You could then have it turn on/off from a sperate 240V charge relay and ACC.

If you wanted safe then there would be a main contactor in each box.
Or one between the boxes.
The fuse could be linked in with the emergency stop buttons.

Personally I prefer a box that has 2 big terminals coming out for main traction, 2 small terminals to engage 1 or more internal conactor(s) and a fuse.
A red led that shows when the contactors are active.

The only other thing is the precharge could be skipped by someone who doesn't wait in ACC for long enough.
All depends on the Kelly controller capacitance.
So the short answer is NO but the long answer is YES.
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Post by Johny »

4Springs wrote:I found a relay which is rated at 0.25A for 220VDC - $22 from RS Components. My precharge resistor is 2k, so at 144V this is 0.07A. To precharge, I turn the key to ACC for a couple of seconds before moving to ON.
What if you are not the driver? Others may not leave it in Acc for long enough and cause trauma to your main contactor and controller. I would err on the side of making the precharge as fast as possible so go for a small resistor - in this case around 470 Ohms, 5 or 10 Watt.
4Springs wrote:My DC/DC converter is on all the time.
Again if you are away for a while but want the car drivable...
I would connect it across the controller input and add a relay to the output of the DC-DC so it doesn't drain the 12V battery.

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Post by 4Springs »

Thanks for the feedback, it has made me think...

Yes, Ok, I need to experiment to see about the precharge. I was assuming that the driver would know to leave it in ACC for a few seconds, but it is a good idea to assume nothing of the driver... The way that the key rotates through ACC means that it will always be active for a split second before ON, even if the driver doesn't know about it. I should be able to get an idea of how long it takes to charge by putting a voltmeter across it and connecting the power - it might be long enough, especially with a lower resistance as Johny suggested.

A contactor in each box?
Now you mention it, I do say that I don't want 144V "hanging around", but that is exactly what I'd have. So I could put a contactor in the rear battery box, activated by the ACC position on the keyswitch. I wouldn't need my precharge relay then, I'd use the contactor instead. This contactor would need to be powered during charging though...

I like the idea of putting the fuses on the emergency stop buttons - less connections are a good thing.
I would connect it across the controller input and add a relay to the output of the DC-DC so it doesn't drain the 12V battery
Do you mean that the DC/DC converter would drain the 12V battery if left connected when the high voltage was absent? Surely not? If so, a diode should prevent it.

I did have the DC/DC converter connected across the controller in my first drawing, but these factors pushed me towards the "on all the time" drawing:
• What would happen if I left my lights on when parked? This would quickly drain the 12V battery, leaving me withought the 12V needed to pull the contactor in. So the car would be unuseable - plenty of 144V, but no 12V! I could always get a jump start...
• My demister is a 12V hairdryer, which uses a lot of current - too much for my piddly 12V battery to provide for any length of time. I'll probably want to preheat the car for 5-10 minutes before using it on frosty mornings, so I'll need the DC/DC converter active at that time. Best if the key is not in the ON position in that case.
• If the DC/DC converter was connected across the controller, then it would be powered during my (brief) precharge. This may drain power away from the controller precharge - especially if the 12V battery was flat for some reason, and drew a lot of current.

So now I'm thinking about a contactor in the rear battery box, which is energised by the ACC key position (or when charging). This would mean that I'd ditch the precharge relay, and the DC/DC converter could stay where it is - it would only be on when charging or at the ACC position.


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Post by Richo »

Only one contactor needs the pre-charge usually the final main contactor.
The internal contactors can go on ACC with the additional relay run from 240VAC.

So the short answer is NO but the long answer is YES.
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Post by 4Springs »

Circuit Diagram Mark II

Image

I now have a contactor in the rear battery box. This means that I only have 144VDC when either the key is turned to ACC (or ON, or START), or when the vehicle is plugged into 240VAC. The precharge now occurs whenever 144VDC is present.

The batteries are now divided into isolatable groups, each of 36V. If I turn the key off, press both emergency stop switches, and unplug from the mains, there are no dangerous voltages around.

There is a relay I've called a "latch relay". This enables the drive contactor. The sequence is:
Key position OFF - no driving possible.
ACC - Controller gets precharged. No driving possible. Dash light is on.
ON - Same as ACC. Dash light is on. No driving possible.
START - Dash light goes off. Driving is possible.
ON - Dash light is off. Driving is possible.
ACC - Dash light comes on. Driving not possible.

So to drive, you have to turn the key all the way around to START. Once started, you leave the key in ON to drive. Turning back to ACC disables the drive, and you have to go to START again if you want to drive.
I'll hook up some unused light on the dash (oil perhaps?), so that it is on when you can't drive. This is similar to an ICE - the warning lights are lit to start with, then go out once the motor is started and ready to drive.

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Post by gholm »

The 12v latching relay idea is similar to what I'm planning to put in my van although I don't have a seperate Accessories switch, only ON and START. Good idea for the unused dash lights too.

I have been looking online and found some good ideas at www.the12v.com, where there's a few options built up from regular auto relays.

Particularly http://www.the12volt.com/relays/page5.asp#mtc

Or have you found a specific latching relay you'll use?

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Post by 4Springs »

That's a cool site!
I come from a computing background, so I tend to think of relays as logical gates. I'll write something like "lightson AND NOT keyon = buzzer" - then I'll turn that into relay logic.
I'm imagining that I'll use a normal automotive relay for the latch. They are quite cheap, come with mounting tabs, and should stand up to vibration well.

I have plenty of unused dash lights to choose from. The instrument panel is the same one used for the wagon version of the Brumby, so there are things that don't apply to a ute, such as rear doors and a hatch. There are also a couple that I don't know what they would be. I had fun shining a torch through them all to see what was there. So far I have chosen:
Fuel Gauge - Zeva Fuel Gauge Driver State of Charge.
Temp Gauge - Choose between motor and controller temperature via a switch. Looks like a thermistor will drive this gauge.
"INT TEMP" light (no idea what it would be used for normally!) - Motor overheat switch.
I've also bought a digital tacho, which the Zeva instrument will drive as an ammeter.

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Post by woody »

You could get the temp gauge to have an "auto" mode which just showed the highest temperature - either using a microcontroller, or some analogue stuff.
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Post by 4Springs »

Let's have a go at some "analogue stuff":
Image

The temp gauge goes up when the resistance goes down. I'm assuming that the temperatures of both motor and controller are bad at about the same level. If so, I can use the same value thermistor. If not, I'd use different thermistors, or put in a series resistor in front of one of them...

I have two switches in this diagram. S1 has three positions, Motor, Controller, Auto. S2 has two sets of contacts, and is either on or off.
With S2 off, S1 can select between the motor and controller temperatures.
To go into Auto mode, switch S1 to Auto and switch S2 on. This shows a combination of the two temperatures, rather than the highest. It might give a good indication though, I'd have to try it.

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Post by 4Springs »

I've been quiet for a while, working in the garage. Work at this time of year is a dark, cold prospect, especially in the evenings after I've finished my paid job for the day.
Battery boxes are coming along nicely, if slowly. I'm close to the final assembly of the rear battery boxes, so I'll take some photos as they come together.
I thought I might share my parts list, it may be useful for someone:
Image
Image

You can see that I don't have the motor adapter plate yet, so I don't have a price for that. It is with an engineer; I didn't get an estimate, so I hope it doesn't cost too much!
Other than that, I think I've paid for most of the big ticket items, and the total is just under $11k. This doesn't include the donor vehicle.

Cheers!

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