1961 Bugeye Sprite New member

Hi
You connect one of the armature connections to the battery
The other armature connection to one of the field coil connections
The final field coil connection to the other terminal of the battery

Going by my 11 inch Hitachi it takes a lot of current even at 12v

I threw away the gearbox with my machine and had the motor where the gearbox would have gone

Your motor should be big enough to do the same - I suspect mine would simply destroy your back axle

This has the major advantage that it frees up the whole "engine bay" for batteries

How much range do you need?
THAT is going to be your biggest problem

bugeyejohn said:

Putting the motor where the tranny would normally reside, is the logical thing to do. It would free up a lot of space for batteries.

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I agree, but check that the motor will fit (in width) into that space. Duncan's car has a custom tube frame which can be any size, but with the Sprite you're either fitting into a tunnel designed for a narrow transmission, or modifying.

bugeyejohn said:

I'm just afraid it would lose its sports car feel if it didn't have the transmission.

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I agree that shifting is part of the driving experience, but keeping weight down and avoiding battery mass stuck way out front (which is what most people do in these conversions when they keep the transmission and use up the engine space with a lump of motor) might be more important to preserving the feel of the car.

bugeyejohn said:

I will need about 16kWh to have a range of about 60 miles. Of course we would always like to have more.

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The plug-in hybrids (including the Chevrolet Volt which is a popular source of battery modules for conversions) typically have about 16 kWh of battery capacity. That means an entire set of their modules would work, but for a brushed DC motor with most controllers they need to be reconfigured for lower voltage.

More would be nice, but even 16 kWh is going to be difficult to fit in.

bugeyejohn said:

If you are not familiar with Bugeyes, they have no trunk lid. You access the trunk area from behind the seats in the cockpit area. I may have to cut out the trunk floor and build a battery box that installs from underneath the car.

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I like that battery box idea. I assume that this means cutting out the floor above the fuel tank, and building the box to occupy both the space originally containing the fuel tank and the space occupied by the spare tire above the floor. This is unfortunately right out at the rear end of the car, which is not good for dynamics (handling), so don't try to put all of the battery there.

If by some miracle you can get in enough battery without filling the engine bay to the top, perhaps a shallow front trunk over the front battery pack (or over the motor, if you keep the transmission) could replace some of the original trunk volume?

bugeyejohn said:

Still not able to get the DC motor to run. I may have wasted $250. If I couldn't use it in the Sprite maybe I could use it in a future project or sell it. Now I'm considering using an AC motor connected directly to the drive shaft. Ill need the battery room. Hoping not to be too disappointed about losing the tranny.

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It's time to take you multimeter out and have a look at that motor

First the field coils - should be less than 0.1 Ohms

Then the Armature - again less than 0.1 Ohms

Use the meter to test both the field and the armature to the carcass - should be in the MegaOhm range

Possibilities
- Unlikely - you have mistaken a temperature sensor for a field coil

More likely - your brushes are hanging up and not contacting the commutator

When you couple the 12v battery do you get a spark?
A 12v battery connected to a motor like that will draw several hundred amps for a second or two

If no "spark" then something is wrong

Are all four of the brush holders insulated from the end plate?
How are the two bolts for connections wired, each to adjacent brush pairs, or to opposite pairs?
Have you tried one 12v battery to the field terminals, and another battery, tried both ways, to the armature terminals?

[Whilst trying to understand this topic I found:
https://www.physicsforums.com/threads/four-carbon-brushes-for-a-dc-motor-what-are-they-for.927521/
which has an interesting picture of what an overspeeded armature on a series motor can look like:

The pictures show how the motor is currently hooked up. I have tried it in every available option with the same results. In one of the pictures you can see two black connectors with no wires going to them. I do not know what they are for. Could they be for some kind of starting voltage? The armature, commutator and field coils all look good. The brushes are good and move freely in their cages. the resistance through the armature and field is 0.8 ohms.

Thanks bug,
The 2 black plastic connectors are for thermal sensor and brush wear indicator (bwi). Do not use those for now.

On the 4 power terminals, the two in the steel frame are S1 & S2 for series field coils, or F1 & F2 if shunt (or separately excited, SepEx) field coils have been used. The two power terminals on the commutator end head (ceh) casting are A1 & A2, for the armature (through the brushes). You appear to have wired it as a series wound motor for the test, like A1 to battery, A2 to S1, S2 to other battery terminal.

From looking closely at the photo in post 1, I suspect this is a SepEx wound motor. Series wound field coils typically consist of few turns (like 8 to 12) of rectangular cross section varnished copper ribbon on these type of motors. The photo shows a relatively large gauge round magnet wire used for the coils, perhaps like 50 or more turns per coil. Resistance for the set of 4 field coils measured between the two S or F terminals would be extremely low for series wound coils, like 0.010 ohm. For the SepEx coils, more like 1 to 10 ohms, typically. It is difficult to get accurate readings from a multimeter, likely impossible for less than a half ohm.

Usually for a shunt motor, the field voltage equals the armature voltage so A1 to S1 to battery and A2 to S2 to other battery terminal. For series motors the armature current and field current are the same, and voltages are quite different, wiring covered previously. The SepEx is somewhere in-between. Using 12V for a no-load test on a 36/48V motor, if SepEx, try the shunt connection scheme. If you're using a battery, monitor and record the voltage at the motor terminals. Getting power (current) to the field and having a very low armature voltage could cause the lock you describe. You could try a separate battery for the field and for the armature.

Also, the photos show pretty bad contamination of oil, water, battery acid, and ? The field coils look to me as though they've been too hot for too long. There could be insulation damage causing shorts and/or grounds. It could certainly use professional TLC.

Now.... Is it worth it? I really don't think this is a straight-forward series wound motor. Probably a SepEx, but who knows for sure, maybe some kind of "special", or even a hack. It does look like a GE. Maybe a motor rebuild shop could install a replacement series coil set. I kinda doubt it.

Your donor car looks pretty nice. Consider getting a different motor for it. I am curious about the one you have. Get anywhere with it, please post.

Regards,

major

{edit} I forgot to mention that finding a suitable controller for a SepEx motor capable of EV voltage and power is difficult to say the least. Check that out before putting a lot of effort/expense into the motor if it is actually a SepEx.

Hi, I’m new here and just at the end of a Austin Healey Sprite 71 conversion, Frog eye next if this one is successful.
Using an AC51 motor, Curtis controller and 144v traction pack. Split as 24 batteries in rear and 21 up front approximately 30kwh so should have a reasonable range. Retaining gearbox, no flywheel or mechanical clutch, but with electronic clutch so should still be engaging to drive. These pictures show development and figuring out placement.
Heater will have electric 2x 1Kw selectable heating elements run from traction pack.
I hope to finish in the next two weeks so will post pics when complete and driving.