Interesting. I've never personally seen a two-speed motor like
that, only the kind that hardinge have, where the controller
switches the configuration from star to delta to pole change.


I have posted an exhaustive description of a Hardinge consequent-pole
two-speed motor control, as found in the later model TL (Toolroom
Lathe, AKA, T-10), on the Hardinge-Lathe Yahoo! group:

http://groups.yahoo.com/group/Hardin...he/message/272

Lower initial cost, and a smaller frame size are reasons for
specifying this type of motor, over an otherwise equivalent
two-winding motor.

These motors are usually constant-torque, and are configured as
four-pole, parallel-star (2Y) and eight-pole, series-delta, using one
winding.

Peter.

In article , Peter H says...


Interesting. I've never personally seen a two-speed motor like
that, only the kind that hardinge have, where the controller
switches the configuration from star to delta to pole change.


I have posted an exhaustive description of a Hardinge consequent-pole
two-speed motor control, as found in the later model TL (Toolroom
Lathe, AKA, T-10), on the Hardinge-Lathe Yahoo! group:

http://groups.yahoo.com/group/Hardin...he/message/272

Unfortunately not visible to me.
Possible to post in dropbox?

Lower initial cost, and a smaller frame size are reasons for
specifying this type of motor, over an otherwise equivalent
two-winding motor.

These motors are usually constant-torque, and are configured as
four-pole, parallel-star (2Y) and eight-pole, series-delta, using one
winding.

Sounds like the person at the top was talking about the same
kind of motor - the motors I'm used to seeing in hardinge
machineare are four or eight pole, switched from star to
delta to obtain the speed change. Not with just one winding
though.

Are the consequent pole motors truly different?

Jim

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A
HREF="http://groups.yahoo.com/group/Hardinge-Lathe/message/272"http://gro
ups.yahoo.com/group/Hardinge-Lathe/message/272/A

Unfortunately not visible to me. Possible to post in dropbox?


I will try.

In the mean time, see below.

[ snip ]



Sounds like the person at the top was talking about the same kind of motor -
the motors I'm used to seeing in hardinge machineare are four or eight pole,
switched from star to delta to obtain the speed change. Not with just one
winding though.

Are the consequent pole motors truly different?


These are either constant-torque (the most common, and the type used by
Hardinge), variable-torque, or constant horsepower (rarely seen).

There is only one winding, but it is distributed across eight poles and three
phases.

Since there is only one winding, the required slot size, and, consequently, the
required frame size, is reduced.


TL (T-10) Late Model Starter

From: http://groups.yahoo.com/group/Hardin...he/message/272

Revised 2/20/2004 (Paragraphs prefixed by "| ").

Hardinge released a magnetic-type starter for the TL (T-10) in about March
1947, replacing the manual-type starter found on earlier machines.

(March 1947 isn't necessarily the precise date for its introduction, however,
this date, "3/47", is printed on the bottom of the diagram posted by Jim in his
"Jim's T-10" photo section).

Normally, for a "consequent-pole" motor, one five-pole and one three-pole
magnetic starters are required. Hardinge implemented this starter with one
three-pole magnetic starter, and a drum switch of unusual configuration.

Now, that is for the high/low speed function alone; the forward/reverse
function is also implemented using a drum switch, although its configuration is
conventional.

Referring to the schematic posted by Jim ...

Hardinge drew this schematic diagram in an unconventional way, breaking the
high/low drum switch into four sections of two apparent poles each, and the
forward/reverse drum switch into three sections, with two apparent poles in the
first two sections and one pole in the last section.

However, there are really only five poles in the high/low switch and three
poles in the forward/reverse switch, which is consistent with most manual-type
consequent-pole starters which provide for reversing.

In order to better describe the March 1947 Hardinge control, I will re-label
the sections and poles of the high/low switch as follows, from top to bottom:

1) Sections 1a and 1b: wires 3, T5 and T3; fast and slow, respectively,

2) Section 2: fast only,

3) Section 3: fast only,

4) Sections 4a and 4b: wires 1, T1 and T6; slow and fast, respectively,

5) Sections 5a and 5b: wires 2, T2 and T4; slow and fast, respectively.

(Wires 1, 2, and 3 come from the reversing switch, and represent the three
phases, but not necessarily Phases A, B and C, as will be described later).

In the center, or off position, no connections are made.

In the fast position, wire 3 is connected to T5 by section 1a, using a terminal
of section 1b; wire 1 is connected to T6 by section 4b; and wire 2 is connected
to T4 by section 5b, additionally, T1, T2 and T3 are connected together by
sections 2 and 3.

In the slow position, wire 3 is connected to T3 by section 1b, using a terminal
of section 2; wire 1 is connected to T1 by section 4a, using a terminal of
section 4b; and wire 2 is connected to T2 by section 5a, using a terminal of
section 5b.

| The above described connections accomplishes the switching of the classical
four-pole consequent-pole, constant-torque, two-speed motor. The motor is
operated in four-pole parallel-star (2Y) mode for high speed, and in eight-pole
series-delta mode for low speed.

The reversing drum switch is perhaps a little easier to understand.

I will re-label the sections and poles of the reversing switch as follows:

| 1) Sections 1a and 1b: wire L1; forward and reverse, respectively,

2) Sections 2a and 2b: wire L3; forward and reverse, respectively, and

3) Section 3: wire L2; forward or reverse.

| In the center, or off position, no connections are made.

In the forward position, wire L1 is connected to wire 1 by section 1a, using a
terminal of section 1b and a terminal of section 2b; wire L3 is connected to
wire 3 by section 2a, using a terminal of section 2b; and wire L2 is connected
to wire 2 by section 3.

In the reverse position, wire L1 is connected to wire 3 by section 1b, using a
terminal of section 2a; wire L3 is connected to wire 1 by section 2b; and wire
L2 is connected to wire 2 by section 3.

The above described connections accomplishes the reversing of the generalized
three-phase motor.

(Wires L1, L2 and L3 represent phases A, B and C, respectively; wires 1, 2 and
3 represent these phases, after reversing, if any, has been applied. Phase B/L2
are not reversed).

Hardinge's March 1947 design incorporates a standard NEMA Type 0 magnetic
starter, for both low-voltage control (high-voltage control is an option) and
for motor running protection, avoiding the complications of a purpose-built
consequent-pole-type magnetic starter, while retaining the extant manual
consequent-pole and reversing drum switches, which were apparently adapted from
an earlier version of the TL.

This innovative control design has the obvious advantages of a magnetic
starter, and low-voltage control (unless high-voltage control was specified),
at significantly lower cost. However, the schematic diagram is somewhat
counterintuitive.

Many thank to Jim [ Jim S. ] for posting the March 1947 schematic diagram.

Peter.


a
href="http://photos.groups.yahoo.com/group/hardinge-lathe/vwp?.dir=/Jim%27
s+T-10&.dnm=Wiring+diagram.jpg&.src=gr&.done=http%3a//photos.groups.yahoo.
com/group/hardinge-lathe/vwp%3f.dir=/Jim%2527s%2bT-10%26.dnm=Wiring%2bdiag
ram-1.jpg%26.src=gr"Previous/a

In article , Peter H. says...

Normally, for a "consequent-pole" motor, one five-pole and one three-pole
magnetic starters are required. Hardinge implemented this starter with one
three-pole magnetic starter, and a drum switch of unusual configuration.

In some of their machines (for example the older milling machines)
they simply use two drum switches. The first is a common
forward/off/reverse drum switch that is wired in the conventional
way, with center off and one pair of lines is interchanged in
one of the on positions, to reverse the motor.

The other drum switch does indeed have more poles, but it is
a bit more complicated in it's operation. The rotor in the
switch is special purpose to run a pole changing motor. Here
again center is off and no contacts ring through. Its
purpose is to correctly connect the three incoming power
lines to the six (for a single voltage motor) motor leads.

Consider the motor windings to be set up in star configuration,
with the center of the star all common. However each
winding has a center tap midway along its length. This
gives a total of six wires emerging from the motor, three
'ends' and three 'centertaps.'

In low speed the center taps are not connected to anything,
and the ends of the star windings are connected to the incoming
lines as in any regular three phase motor.

However in high speed the incoming lines are connected instead
to the centertap wires, and the ends of the star windings
are all tied to each other, and do not connect to any other
power lead. (this effectively halves the number of poles
and makes the motor run faster)

Switching is accomplished by hardinge in a variety of ways. My
milling machine for example has a single drum switch with
six rotors in it, and each rotor has internal connections
such that the three wipers on one side of the switch are
correctly commutated to the six wipers on the other side.
This thing has a vaguely enigma-like quality and it took
me about three nights of sweating before I married it to
the motor and got it all wired up right. It's not the stock
drum control for that machine btw.

In my DSM-59 they do it in another way: here is a photograph
of the switchgear for that machine:

http://www.metalworking.com/DropBox/_2001_retired_files/DSM5.jpg

Wherein you will see two separate drum controllers. The right
hand one is the normal forward/off/reverse type. The black
disks on the shafts are cams, and the bottom-most cam actuates
its switch in both positions, the upper two pairs operate
alternately in forward and reverse, and serve to reverse the
two remaining incoming lines.

The left hand drum controller does the speed control.
Unfortunately I took the photo from the wrong side so
you cannot get a good view of the jumpers on the extreme
left side of the switches, but one can see that the
wires that enter into the switches from the left are
(top to bottom) white, black, white; and white, black, white;
and then at the very bottom they are again white black white.

The lowest trio is there, take it on faith.

The black wires are the incoming power lines (suitably
rendered by the reversing switch) and the white leads are
the motor wires, which go off in greenfield conduit to
the motor itself.

If one were to label the cams, top to bottom, as 1 to 8,
they operate as follows.

High speed, cams 1, 3, 4, 6 and 8 actuate their switches.

Low speed, cams 2, 5, and 7 actuate their switches

The reason that the high speed has two extra cams, is
so that the ends of the star windings can be all
tied together. Otherwise the contactors either choose
incoming lines to go to either 'ends' or 'centertaps'
of each motor winding.

This is a good deal more complicated in the telling, than
in the reality. There is also a good schematic on the
inside of the door cover if anyone wanted a snapshot of it.

Jim

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