Gas Engine Magazine

The Application Of Sumter Magnetos

By Staff

Rex Box P, Bedford, MA 01730

Sumter magnetos were used on many early engines, Fairbanks Morse
being one of the most popular. These early all brass magnetos are
extremely well made and marked SUMTER TELEPHONE MFG. CO. SUMTER SO.
CA. Sometime before 1919, Sumter was purchased and incorporated as
the Sumter Division of Splitdorf Electrical Company at 1466
Michigan Ave, Chicago IL. The Sumter name was retained for magnetos
made by Splitdorf at their Sumter Division. In many references I
have seen, the name Sumter is commonly misspelled as Sumpter.

I was fortunate in being able to locate an early Sumter manual
dated 3/19/19. With less than 20 Splitdorf branch houses and
service centers in the United States, a couple dozen manuals were
sufficient to supply all the centers. Because so few copies were
needed, many pages of the manual were hand typed carbon copies.
Below is an exact copy as it appears from certain hand typed manual
pages dated 3/19/19. It should prove useful to readers who are
trying to identify Sumter magnetos and determine their recommended
application.

SUMTER MAGNETOS

The following is a list of practically all the models of Sumter
magnetos which have ever been manufactured, with a brief
description of what each one is and how it can be identified:

IMP #10 The original IMP magneto had low
magnets, about an inch shorter than the present IMP. There was no
magnet band over the top. Current was taken off the collector ring,
brush being located in the top plate. Timing marks on the end of
the shaft or bearing, long since discontinued.

IMP #11 This magneto was successor to No. 10.
Has magnets about an inch higher. Has magnet band over the top, on
which is No. 11. Current taken off the collector ring, brush being
located on top plate. Timing marks on end of shaft and bearing.
Supplied with armature with #22 and #23 wire. Our latest production
and repairs have #26 wire. Discontinued about 1916.

IMP #12 This is the same magneto as #11, except
it has outstanding lugs or ears on each side of the base.
Manufactured exclusively for Fairbanks-Morse. But furnished also
with reversed base in small quantities to some other concerns, then
known as #12-R. Discontinued about 1916.

IMP #14 This magneto was made special for
plugoscillator work. Has tapered shaft, no timing arrangement;
current is taken off the hardened end of the armature shaft by a
button carried in a Bakelite terminal cap. Has magnet band with #14
on it. Magnets, frame, etc. about the same in dimensions as the IMP
#11. This is a current model. Armature wound with #26 wire. All
except our earliest production has oil well bearings.

IMP #15 This magneto is the successor to the
IMP #12, and has the same type of base. Has terminal cap, taking
current off end of armature shaft. Magnet band shows #15. Straight
shaft with timing disc. Has oil well bearings; No. 26 wire
armature. Current model.

IMP #16 This magneto is exactly like #15,
except that it has a square base, with lugs. This is the successor
of the IMP #11. Current model.

SATAN #20 The original Satan model, no magnet
band. Current taken from end of armature shaft by a brush inside of
a fibre brushing. Has timing disc. Long since discontinued.

SATAN #21 This model corresponds in all
respects to the IMP #11, except that it is larger.

SATAN #22 This model corresponds in all
respects to the IMP # 12 except that it is larger.

SATAN #23 There was one small shipment of SATAN
magnetos which left the Sumter factory marked SATAN #23. This
designation was later changed, however, to #25.

SATAN #25 This magneto is the successor of #22.
It has the same lugs on the base, has magnet band marked #25. Has
current collector on the end of armature shaft, carried in Bakelite
cap; has timing disc, #26 wire armature. In fact, corresponds in
all respects to IMP #15 but is larger.

SATAN #26 This magneto is just the same as #25
except that it has a square base.

J-R This is one of the original standard Sumter
magnetos and is marked JR on the older models; JRS on some models;
JRCS on some models, all of those designating some slight changes.
The original models had the magnets held on with screws running
through them. These magnets are single, no lamination, except on
the JRL, very few of which were made for Lauson with laminated
magnets. The present model JR-30 is marked JR-30 on the magnet
band; has porcelain terminal taking current from end of magnet
shaft.

B-N This magneto is larger than the JR but made
in the same way. Has single magnets, porcelain terminal, timing
disc. One of the original Sumter models. A limited quantity
manufactured.

BN-R This model is the same as model B
Standard, except that it has a tapered shaft corresponding to the
taper used on the Bosch NR magneto.

B-40 This magneto was one of Sumter’s
standard magnetos, having laminated magnets, bronze end plates,
porcelain terminal and is marked #B.

BD This is the same as the model B except that
the armature is wound with larger wire, giving lower voltage for
special work.

BS This magneto is the model B modified and
mounted in a tilting cradle for advance and retard.

BSD This model is the same as the BS, except
that the armature is wound with larger wire, giving lower
voltage.

AP-40 This is the original standard Sumter
magneto with three laminated magnets, brass end plates, porcelain
terminal, Marked AP.

AP-AR-3 This is the same as the model AP except
that it has a tapered shaft, to agree with the Bosch model AR-3
magneto.

APD This is the same as the model AP except
that it has a lower voltage armature for special work. Marked
APD.

AS This is the model AP magneto somewhat
modified and mounted in a swinging cradle so as to get advance and
retard.

ASC A few special magnetos made up for Foos Gas
Engine Company some years ago.

ASD This is the same as the Model AS, except
with a lower voltage armature.

AG This a larger Sumter magneto, has the same
construction as the Model AP, except wick oilers on the bearings
and magnets considerably higher, giving greater output.

AGD This the same as Model AG, except with low
voltage armature. Some of these were made up without special
designation, but with tapered shaft instead of straight shaft.

300 This is the JR magneto with tapered shaft,
arranged with two horizontal springs to make it an oscillator.

301 This is the JR magneto with tapered shaft,
arranged with one vertical spring to make it an oscillator.

400 This is the B magneto equipped with two
horizontal springs and a tapered shaft to make it an
oscillator.

401 This is the B magneto, equipped with
tapered shaft and one vertical spring to make it an oscillator.

500 Model AP magneto, equipped with tapered
shaft and two horizontal springs to make it an oscillator.

502 This is the AP magneto, equipped with
tapered shaft and one vertical spring to make it an oscillator.

503 This is the model AP magneto with tapered
shaft and two vertical springs to make it an oscillator.

MAGNETOS RECOMMENDED FOR H. P. AS FOLLOWS

IMP 1 h.p. or in some cases 1 ? h.p.
SATAN 2 to 2? h.p.
JR Up to 4 and sometimes 6 h.p.
B 6 to 10 h.p.
BH 5 and 6 h.p.
AP 10 h.p. and up
AG Very large motors 29 h.p. and up
BS Only when range is excessive.
AS Only when range is excessive.
RT Dixie 1 to 4, not over 3 ? h.p.
DIXIE 10 and 20, not over 3 ? h.p.
DIXIE M-1 up to 4 ? h.p.
DIXIE M-2 up to 4 ? h.p.
  • Published on Nov 1, 1989
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