DIY Electric Car Forums banner
1 - 5 of 5 Posts

·
Registered
Joined
·
66 Posts
Discussion Starter · #1 ·
I know that a series has a different power distribution, wire gauge, and wire length than a sepex.

I want a battery pack voltage total of 120-144v

So I could make a total of 144v by splitting the total into a 60v pack, routed to a controller for the field, and a 84v pack to a controller routed to the armature. I would like to be able to connect the packs into the total pack.

Splitting the total based on the theoretical, mysterious, voltage sharing of a series motor.

Right? I hope...

If this works, I have another theory :p
 

·
Registered
Joined
·
7,791 Posts
I know that a series has a different power distribution, wire gauge, and wire length than a sepex.

I want a battery pack voltage total of 120-144v

So I could make a total of 144v by splitting the total into a 60v pack, routed to a controller for the field, and a 84v pack to a controller routed to the armature. I would like to be able to connect the packs into the total pack.

Splitting the total based on the theoretical, mysterious, voltage sharing of a series motor.

Right? I hope...

If this works, I have another theory :p
Sorry, you're way off base. There is nothing mysterious about a series wound motor. The important thing is the field current equal the armature current. The ratio of armature voltage to field voltage depends on load and speed but for a ball park use 100 to 3.

I have seen a case or two where for unusual reasons it has been done. It takes a thorough understanding of the series motor and design of two unique pwm controllers with a common control.

If for some reason you're set on the idea, study up on DC motor theory and control.

major
 

·
Registered
Joined
·
66 Posts
Discussion Starter · #3 · (Edited)
The amperage is the same for field and armature. The voltage can be different for either, but total to supply voltage. I called that the split. That is the same as ratio.

I was concerned about PWM timing, I'm assuming the frequency is rather high. Why not run a large capacitor on the output?
 

·
Registered
Joined
·
66 Posts
Discussion Starter · #5 ·
Ah ha!

Magnetic field strength is defined by amperage! Derp! Now I feel dumb :p

Then:
http://curtisinstruments.com/index.cfm?fuseaction=cProducts.DownloadPDF&file=1244 (13E)1.pdf

Page 39:
"FIELD MAP
The field map parameter defines the variation of the field winding current as a
function of armature current. It controls how much field current is applied for a
given armature current, and is adjustable from 0% to 100%, in 5% increments."

I could measure the amperage the armature controller supplies, and replace the throttle of a field controller with the measurement!

Working out details now requires some determination of the ratio (of an undefined motor)...
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top