AC fractional synchronous motor

[Richard]

I have a well-made vintage motor (used in a vintage professional chart
recorder)and the motor is marked "Synchronous". (Evershed & Vignoles
type FCX31/AS15 and it's about 2 long and 2" diameter).

Four coloured wires come out of it and seem to be marked as follows:

Blue: "1"
Yellow: "2"
Red: "X"
Green: "Y"

"1" - Connects to "X" and a wire that goes to capacitor.

"2" - Connects to a capacitor. Also to wire that goes somewhere.

"X" - connects to "1".

"Y" connects to possibly a switch inside the paper drive mechanism, and
a wire that goes somewhere.


But anyway, here we have a two -winding device and it's a synchronous
motor. I think the capacitor may be used for starting purposes.

AC 240V must connect to this motor, but I don't know how to solve which
terminals the AC should be connected to. Can anyone help me determine
the solution. Thanks.

 

[Jasen Betts]

I have a well-made vintage motor (used in a vintage professional chart
recorder)and the motor is marked "Synchronous". (Evershed & Vignoles
type FCX31/AS15 and it's about 2 long and 2" diameter).

Four coloured wires come out of it and seem to be marked as follows:

Blue: "1"
Yellow: "2"
Red: "X"
Green: "Y"

"1" - Connects to "X" and a wire that goes to capacitor.

"2" - Connects to a capacitor. Also to wire that goes somewhere.

"X" - connects to "1".

"Y" connects to possibly a switch inside the paper drive mechanism, and
a wire that goes somewhere.

But anyway, here we have a two -winding device and it's a synchronous
motor. I think the capacitor may be used for starting purposes.

split-phase motor using capacitor

| in |
| |
+--wwwwwww-+
| |
| _ 3
\ / \ 3
\ Rotor 3
| \_/ 3
| 3
+---||-----+


if you oick the wrong two terminals it'll run backwards.
capacitor-run motors don't have the switch.


-
⚂⚃ 100% natural

 

[Richard]

split-phase motor using capacitor

| in |
| |
+--wwwwwww-+
| |
| _ 3
\ / \ 3
\ Rotor 3
| \_/ 3
| 3
+---||-----+


if you oick the wrong two terminals it'll run backwards.
capacitor-run motors don't have the switch.


-
⚂⚃ 100% natural

I've just found out that the motor must have an open coil.

2K between Blue and Yellow ("1" & "2") No continuity between Red and
Green ("X" & "Y").

So, I cannot do anything with this motor. :c(

 

[Richard]

Keep looking, it may be fine.

Purely synchronous machines only work when they're already spinning at
close to synchronous speed. So real-world synchronous machines have some
scheme to start them up (usually as an inductive machine), then a way to
switch them to being synchronous. Often the rotor will be shorted during
startup, then driven with a DC current for synchronous operation. This
_may_ happen with a centrifugal switch inside the motor. If so, the DC
current wire would appear as an open circuit until the motor is up to
speed.

I connected an ohmmeter across "X" and "Y". No continuity even when
rotor spins at full speed of an electric drill (used to spin the rotor).

Although this motor is marked synchronous, it does not (appear) to have
a permanent magnet rotor, or means of energising the rotor.

Okay, so I looked into the paper-feed mechanism (of a vintage chart
recorder) that the motor is part of. The paper-feed mechanism is in two
parts (LH and RH)which are physically connected by way of having a
common spindle.

Terminals on LH side I thought led to a centrifugal switch, but in fact
go to a Crouzet synchronous motor (Type 392). This is I believe is
self-starting (reluctance / hysteresis - whatever).

The shaft of this synchronous motor (on the LH side) connects to the
shaft of the motor I'm examining (on the RH side) which is simply marked
"synchronous". But, the connection is not solid, I mean there's a kind
of one direction clutch in-between the two motor spindles. It does not
transmit torque one way, but does the other.

So, for the paper-drive mechanism we have:

RH LH

---M1------Clutch------M2----

M1 is the Crouzet synchronous motor connected via the one way clutch to
M2 the motor marked "synchronous".

Now, the speed of the paper feed could be set electrically by a simple
manual (spst)switch. That changes speed of paper drive by a factor of 60.

I personally cannot see M1 being powerful enough to drive the paper
feed, but am no expert and might. M1 the Crouzet motor is like the motor
you get on a microwave cooker. M2 looks like a precision engineered unit.

A capacitor seems to permanently connected across "1" and "2", of the
coil with continuity.

I'll try to supply a circuit.

Is M2 really a motor I now ask myself. :c)

 

[Richard]

Keep looking, it may be fine.

Purely synchronous machines only work when they're already spinning at
close to synchronous speed. So real-world synchronous machines have some
scheme to start them up (usually as an inductive machine), then a way to
switch them to being synchronous. Often the rotor will be shorted during
startup, then driven with a DC current for synchronous operation. This
_may_ happen with a centrifugal switch inside the motor. If so, the DC
current wire would appear as an open circuit until the motor is up to
speed.

http://www.vintage-radio.net/forum/attachment.php?attachmentid=46190&d=1296912295

I think it is just a small induction motor. I feel no "stepping" as I
turn the shaft.

 

[Richard]

Keep looking, it may be fine.

Purely synchronous machines only work when they're already spinning at
close to synchronous speed. So real-world synchronous machines have some
scheme to start them up (usually as an inductive machine), then a way to
switch them to being synchronous. Often the rotor will be shorted during
startup, then driven with a DC current for synchronous operation. This
_may_ happen with a centrifugal switch inside the motor. If so, the DC
current wire would appear as an open circuit until the motor is up to
speed.

http://www.vintage-radio.net/forum/attachment.php?attachmentid=46190&d=1296912295

I think it is just a small induction motor. I feel no "stepping" as I
turn the shaft.

If no continuity between red and green, this item surely is no good.

I'd say it is a motor myself. Terminals marked "1" "2" "X" "Y".

 

[Jamie]

I connected an ohmmeter across "X" and "Y". No continuity even when
rotor spins at full speed of an electric drill (used to spin the rotor).

Although this motor is marked synchronous, it does not (appear) to have
a permanent magnet rotor, or means of energising the rotor.

Okay, so I looked into the paper-feed mechanism (of a vintage chart
recorder) that the motor is part of. The paper-feed mechanism is in two
parts (LH and RH)which are physically connected by way of having a
common spindle.

Terminals on LH side I thought led to a centrifugal switch, but in fact
go to a Crouzet synchronous motor (Type 392). This is I believe is
self-starting (reluctance / hysteresis - whatever).

The shaft of this synchronous motor (on the LH side) connects to the
shaft of the motor I'm examining (on the RH side) which is simply marked
"synchronous". But, the connection is not solid, I mean there's a kind
of one direction clutch in-between the two motor spindles. It does not
transmit torque one way, but does the other.

So, for the paper-drive mechanism we have:

RH LH

---M1------Clutch------M2----

M1 is the Crouzet synchronous motor connected via the one way clutch to
M2 the motor marked "synchronous".

Now, the speed of the paper feed could be set electrically by a simple
manual (spst)switch. That changes speed of paper drive by a factor of 60.

I personally cannot see M1 being powerful enough to drive the paper
feed, but am no expert and might. M1 the Crouzet motor is like the motor
you get on a microwave cooker. M2 looks like a precision engineered unit.

A capacitor seems to permanently connected across "1" and "2", of the
coil with continuity.

I'll try to supply a circuit.

Is M2 really a motor I now ask myself. :c)

It's a long shot how ever, you may have a brushless AC type that has a
partially integrated field for the DC part.. Most of the brushless
types have their own 3 pole rectifiers on the rotor assembly connected
to the coils, just for low DC current as needed.. Larger motors normally
also include a stator field that is rectified to produce a DC field for
which rotor assembly on the DC source spins through to derives it's
energy. Like I said, most do all this inside and have electronics or
a centrifugal switch on those that has a combination squirrel case motor
to get started. (self starting)

The type of motor you have, is not self starting, obviously.. which
most likely explains the need for the clutch from another source to
get it started ? That being the case, I think what you have there is a
motor that may have a bridge rectifier in it on one set of the Leeds
that needs the be energized when the external start motor disconnects
to put the motor into full operating sync mode.

The verify this.. Put your meter in Diode test mode and see if you can
get ~ 1.2 reading on one set of the leads(swapping leads).. If so, these
leads need to be energized with some AC/DC volts to produce the field
needed for the brushes field inside. This field most likely can be
turned at the same time as the main stator if the starting motor has
enough torque to over come the synchronized locked rotor. This may
explain why you are getting a seemingly open effect on one of the pairs,
when testing.

Most of these motors are 3 phase how ever, you may have a split phase
type (2 phase 180 poles) and it needs to be spinning into the desired
direction to start..


Jamie

 

[Richard]

It's a long shot how ever, you may have a brushless AC type that has a
partially integrated field for the DC part.. Most of the brushless
types have their own 3 pole rectifiers on the rotor assembly connected
to the coils, just for low DC current as needed.. Larger motors normally
also include a stator field that is rectified to produce a DC field for
which rotor assembly on the DC source spins through to derives it's
energy. Like I said, most do all this inside and have electronics or
a centrifugal switch on those that has a combination squirrel case motor
to get started. (self starting)

The type of motor you have, is not self starting, obviously.. which
most likely explains the need for the clutch from another source to
get it started ? That being the case, I think what you have there is a
motor that may have a bridge rectifier in it on one set of the Leeds
that needs the be energized when the external start motor disconnects to
put the motor into full operating sync mode.

The verify this.. Put your meter in Diode test mode and see if you can
get ~ 1.2 reading on one set of the leads(swapping leads).. If so, these
leads need to be energized with some AC/DC volts to produce the field
needed for the brushes field inside. This field most likely can be
turned at the same time as the main stator if the starting motor has
enough torque to over come the synchronized locked rotor. This may
explain why you are getting a seemingly open effect on one of the pairs,
when testing.

Most of these motors are 3 phase how ever, you may have a split phase
type (2 phase 180 poles) and it needs to be spinning into the desired
direction to start..


Jamie

Do I have an hysteresis synchronous motor a bit like:

http://www.globalspec.com/FeaturedProducts/Detail/ARCSystems/HYSTERESIS_SYNCHRONOUS_MOTORS/118185/0

 

[Richard]

It's a long shot how ever, you may have a brushless AC type that has a
partially integrated field for the DC part.. Most of the brushless
types have their own 3 pole rectifiers on the rotor assembly connected
to the coils, just for low DC current as needed.. Larger motors normally
also include a stator field that is rectified to produce a DC field for
which rotor assembly on the DC source spins through to derives it's
energy. Like I said, most do all this inside and have electronics or
a centrifugal switch on those that has a combination squirrel case motor
to get started. (self starting)

The type of motor you have, is not self starting, obviously.. which
most likely explains the need for the clutch from another source to
get it started ? That being the case, I think what you have there is a
motor that may have a bridge rectifier in it on one set of the Leeds
that needs the be energized when the external start motor disconnects to
put the motor into full operating sync mode.

The verify this.. Put your meter in Diode test mode and see if you can
get ~ 1.2 reading on one set of the leads(swapping leads).. If so, these
leads need to be energized with some AC/DC volts to produce the field
needed for the brushes field inside. This field most likely can be
turned at the same time as the main stator if the starting motor has
enough torque to over come the synchronized locked rotor. This may
explain why you are getting a seemingly open effect on one of the pairs,
when testing.

Most of these motors are 3 phase how ever, you may have a split phase
type (2 phase 180 poles) and it needs to be spinning into the desired
direction to start..


Jamie

Do I have an hysteresis synchronous motor a bit like:

http://www.globalspec.com/FeaturedProducts/Detail/ARCSystems/HYSTERESIS_SYNCHRONOUS_MOTORS/118185/0

Same colours for wires. (Not that that necessarily means much).

 

[Jamie]

Do I have an hysteresis synchronous motor a bit like:

http://www.globalspec.com/FeaturedProducts/Detail/ARCSystems/HYSTERESIS_SYNCHRONOUS_MOTORS/118185/0

You would need to take that apart and look at the rotor to determine
that. It should still have some small magnetic properties in it from the
last run cycle. But those are not a good motor to use if you want to
have it fall back in place on the next start up because the magnetics
in the core can change position. After all, you must remember the stator
in this case is the only thing that is polarizing it and until it
reaches it near speed it isn't going to be fixed.

This is the case like one starting in squirrel cage mode and then
switching over to synch mode. Only its done with out switches of course.
Once the speed gets near normal then poles on the core magnetized tracks
with the line frequency, Hence the term hysteresis which in magnetics
means that it holds its last value of
polarization for a bit before fading away or being canceled by another.

In the case of IDing it, the rotor should be smooth with no lines and
no wire on it.


Personally, and its just me of course, I would say the Green wire is
a case ground and the other three are just standard capacitor start type
of set up.. If that being the case, one of those wires are the center
tap for example. We have at work, motors we use that are synch motors
with the blue wire as the common and you select either the RED or Black
wire for the connection from the L1 and then use the cap from that L1
connection over to the other remaining lead. Basically, we just have the
cap across the Black and Red wire, connect L2 to the blue wire and
then depending on which direction we need to go, we just connect the L1
to either the Red or black wire, leaving the cap connected across those
same Red and Black wires..

If you put the meter on these leads, the blue wire is the center tap
and the cap is being used to produce the phase shift with the other
winding. and our green wire is just a case ground.

Have a good day..

Jamie

 

[Richard]

You would need to take that apart and look at the rotor to determine
that. It should still have some small magnetic properties in it from the
last run cycle. But those are not a good motor to use if you want to
have it fall back in place on the next start up because the magnetics
in the core can change position. After all, you must remember the stator
in this case is the only thing that is polarizing it and until it
reaches it near speed it isn't going to be fixed.

This is the case like one starting in squirrel cage mode and then
switching over to synch mode. Only its done with out switches of course.
Once the speed gets near normal then poles on the core magnetized tracks
with the line frequency, Hence the term hysteresis which in magnetics
means that it holds its last value of
polarization for a bit before fading away or being canceled by another.

In the case of IDing it, the rotor should be smooth with no lines and
no wire on it.


Personally, and its just me of course, I would say the Green wire is
a case ground and the other three are just standard capacitor start type
of set up.. If that being the case, one of those wires are the center
tap for example. We have at work, motors we use that are synch motors
with the blue wire as the common and you select either the RED or Black
wire for the connection from the L1 and then use the cap from that L1
connection over to the other remaining lead. Basically, we just have the
cap across the Black and Red wire, connect L2 to the blue wire and
then depending on which direction we need to go, we just connect the L1
to either the Red or black wire, leaving the cap connected across those
same Red and Black wires..

If you put the meter on these leads, the blue wire is the center tap and
the cap is being used to produce the phase shift with the other winding.
and our green wire is just a case ground.

Have a good day..

Jamie

Further data here:

http://www.vintage-radio.net/forum/showthread.php?t=65010

I still cannot figure things out. :c)

 

[Cydrome Leader]

http://www.vintage-radio.net/forum/attachment.php?attachmentid=46190&d=1296912295

I think it is just a small induction motor. I feel no "stepping" as I
turn the shaft.

If no continuity between red and green, this item surely is no good.

I'd say it is a motor myself. Terminals marked "1" "2" "X" "Y".

anything that small is probably like the motors used in old tape
recorders and won't have starting switches and junk like that- just a
small capacitor.

the possibly open winding does sound suspect.

 

[Richard]

Keep looking, it may be fine.

Purely synchronous machines only work when they're already spinning at
close to synchronous speed. So real-world synchronous machines have some
scheme to start them up (usually as an inductive machine), then a way to
switch them to being synchronous. Often the rotor will be shorted during
startup, then driven with a DC current for synchronous operation. This
_may_ happen with a centrifugal switch inside the motor. If so, the DC
current wire would appear as an open circuit until the motor is up to
speed.

Thread also here:

http://www.vintage-radio.net/forum/showthread.php?t=65010

Lets just look at what the overall situation is:

This is the machine:

http://www.vintage-radio.net/forum/attachment.php?attachmentid=46003&d=1296589576
-----------
In order that the paper is taken from the spool containing the blank
chart paper, the shaft on the paper feed gearing assembly must rotate CW
(looking from the assembly's shaft end, that is looking RIGHT). If you
bolt a motor onto this gearing assembly it would therefore would need to
be a CCW motor looking at the motor from the spindle end (assuming one
spindle).

..............LEFT..........................RIGHT

---M1>-----Clutch-----<M2>----<SHAFT (CW)

M1 is a 240V self-starting synchronous motor at 25RPM. I presume it's a
50Hz motor. It's direction (looking from it's spindle end) is CW. The
clutch transmits this torque through to M2 (M2's spindle goes right
through the motor, M2 therefore has two spindle ends, to it's left M1,
to it's right the SHAFT).

The clutch does not transmit torque if the spindle from where the torque
is coming from is not in the required direction of rotation.

If M1 was connected via the clutch then directly to the SHAFT (no M2),
the mechanism would actually fail to take up paper from the paper spool.
It would try to feed paper to it.

When M1 is running, if I hold the end of the clutch I can cause M1 to
momentarily reverse, but corrects itself and resumes it's start-up
direction (CW).

But of course, we have M2 in between the clutch and the SHAFT. It
appears then M2 must rotate in a direction opposite to M1, in order that
paper is taken from the spool. In other words, if I position myself to
the right of M2, the shaft of M2 must rotate CCW.

The speed of rotation of the SHAFT can be set by a SPST switch as HIGH
or LOW. The speed difference is a factor of 60. The paper feed rate goes
from so many inches per second to per minute.

At the moment I still feel M2 is a motor.

Remember: About a 50 year-old chart recorder paper feed arrangement. How
does it work?

Here is the circuit if I have made no mistakes. I'm making assumptions
about the coils in M2, but there are 4 wires to M2:

http://www.vintage-radio.net/forum/attachment.php?attachmentid=46264&d=1296998790

------------

Okay, Here we have a situation where the change in SHAFT speed has to
be a factor of 60. SHAFT speed needs to be (I've reckoned) 16.67 RPM
when it's so many inches per minute and 1000 RPM when it's so many per
second.

M1 is a GEARED self starting 240V AC 50Hz synchronous motor. It's speed
is 25 RPM. It's direction is opposite to what SHAFT rotation should be.

M2 is NOT a geared motor and takes same AC mains as M1, which must be
240V 50Hz. Is it likely that M2 will run as a motor at the required
16.67 RPM? I'd say no at 50Hz, but am no expert. It seems a 12 pole
motor. It might run at 1000RPM.

M1 and M2 connected by a clutch that transmits torque, but only if
rotation is correct direction.

If M1's speed was 16.67 RPM and rotating in the proper direction, and M2
was a motor with speed of 1000 RPM, and either (but not both) M1 or M2
was in operation, the problem would be solved. But, this is not
apparently the case. At best M1 is always in operation and M2 is
energised preumably only on high speed.

Working of the machine is not easy to fathom. Needs the manual or
someone familiar with 1950's chart recorder technology.

 

[Richard]

Further data here:

http://www.vintage-radio.net/forum/showthread.php?t=65010

I still cannot figure things out. :c)

It just came to me the error I was making. So simple.

The true picture is this:

SPINDLE M1>----------<CLUTCH>-----------<M2>---------X
X
---SHAFT
X


Bolting on M2 does not put it's axis concentric with SHAFT. The pinion
on M2 spindle cogs with a pinion on SHAFT. And that will lead to a
reversal of whatever way the M1 and M2's spindle turns. So, M1 will make
sprokets move the correct way.

Also, this solves the speed problem. The pinion on the spindle is
smaller than the one on SHAFT. SHAFT needs to revolve at 16.67 RPM, but
the spindle needs to be running at a different speed, at 25 RPM, because
cogs/pinions will reduce the RPM from 25 to 16.67 RPM.

What doea this do for the HIGH speedsituation? The spindle should
rotate 60 times 25 RPM = 1500 RPM. SHAFT turns at 1000 RPM.

This means: *M2 has to be a synchronous motor!*

Mine will be faulty, because I should get continuity for two coils. I
only get one, between blue and yellow and not red and green.