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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.


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