I bet this appears twice now.  it seems to be in limbo, so reposting...




got cheap on ebay a box with forward reverse stop buttons, but that's all it
is, the box and contactors under the buttons.  The start buttons have
push-to-make switches and the stop one has push-to-break.

So... can I make it drive the single-phase motor on the lathe, forward and
reverse, and if so what else does it need.  I already have
stop-start-overload switch thing, but that only goes one way.  It's also not
no-volt release, which is not ideal.

currently, reversing is done with a pair of SPDT switches, which is far from
ideal, especially as they're only just big enough current rating.	
-- 
Austin Shackles.  www.ddol-las.net  my opinions are just that
Travel The Galaxy!  Meet Fascinating Life Forms...
------------------------------------------------\   
   >>  http://www.schlockmercenary.com/  <<      \  ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!

Austin Shackles wrote:
> I bet this appears twice now.  it seems to be in limbo, so reposting...
> 
> 
> 
> 
> got cheap on ebay a box with forward reverse stop buttons, but that's all it
> is, the box and contactors under the buttons.  The start buttons have
> push-to-make switches and the stop one has push-to-break.
> 
> So... can I make it drive the single-phase motor on the lathe, forward and
> reverse, and if so what else does it need.  I already have
> stop-start-overload switch thing, but that only goes one way.  It's also not
> no-volt release, which is not ideal.
> 
> currently, reversing is done with a pair of SPDT switches, which is far from
> ideal, especially as they're only just big enough current rating.	
Dis you see my reply Austin?

Bob

On or around Mon, 18 Aug 2008 18:04:46 +0100, Bob Minchin
 enlightened us thusly:

>Austin Shackles wrote:
>> I bet this appears twice now.  it seems to be in limbo, so reposting...
>> 
>> 
>> 
>> 
>> got cheap on ebay a box with forward reverse stop buttons, but that's all it
>> is, the box and contactors under the buttons.  The start buttons have
>> push-to-make switches and the stop one has push-to-break.
>> 
>> So... can I make it drive the single-phase motor on the lathe, forward and
>> reverse, and if so what else does it need.  I already have
>> stop-start-overload switch thing, but that only goes one way.  It's also not
>> no-volt release, which is not ideal.
>> 
>> currently, reversing is done with a pair of SPDT switches, which is far from
>> ideal, especially as they're only just big enough current rating.	
>Dis you see my reply Austin?
>
>Bob

nope.  whole thread seems to be AWOL.  unless it was by email, in which
case, you need to fix the address, or it goes into a rarely-checked spambin.
-- 
Austin Shackles.  www.ddol-las.net  my opinions are just that
Travel The Galaxy!  Meet Fascinating Life Forms...
------------------------------------------------\   
   >>  http://www.schlockmercenary.com/  <<      \  ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!

Austin Shackles wrote:
> On or around Mon, 18 Aug 2008 18:04:46 +0100, Bob Minchin
>  enlightened us thusly:
> 
>> Austin Shackles wrote:
>>> I bet this appears twice now.  it seems to be in limbo, so reposting...
>>>
>>>
>>>
>>>
>>> got cheap on ebay a box with forward reverse stop buttons, but that's all it
>>> is, the box and contactors under the buttons.  The start buttons have
>>> push-to-make switches and the stop one has push-to-break.
>>>
>>> So... can I make it drive the single-phase motor on the lathe, forward and
>>> reverse, and if so what else does it need.  I already have
>>> stop-start-overload switch thing, but that only goes one way.  It's also not
>>> no-volt release, which is not ideal.
>>>
>>> currently, reversing is done with a pair of SPDT switches, which is far from
>>> ideal, especially as they're only just big enough current rating.	
>> Dis you see my reply Austin?
>>
>> Bob
> 
> nope.  whole thread seems to be AWOL.  unless it was by email, in which
> case, you need to fix the address, or it goes into a rarely-checked spambin.
I replied usenet thus:

"Use your existing stop start overload as the NVR and starter and wire 
the new box as a latching forward/reverse switch.
Bob "

On or around Mon, 18 Aug 2008 21:46:10 +0100, Bob Minchin
 enlightened us thusly:

>Austin Shackles wrote:
>> On or around Mon, 18 Aug 2008 18:04:46 +0100, Bob Minchin
>>  enlightened us thusly:
>> 
>>> Austin Shackles wrote:
>>>> I bet this appears twice now.  it seems to be in limbo, so reposting...
>>>>
>>>>
>>>>
>>>>
>>>> got cheap on ebay a box with forward reverse stop buttons, but that's all it
>>>> is, the box and contactors under the buttons.  The start buttons have
>>>> push-to-make switches and the stop one has push-to-break.
>>>>
>>>> So... can I make it drive the single-phase motor on the lathe, forward and
>>>> reverse, and if so what else does it need.  I already have
>>>> stop-start-overload switch thing, but that only goes one way.  It's also not
>>>> no-volt release, which is not ideal.
>>>>
>>>> currently, reversing is done with a pair of SPDT switches, which is far from
>>>> ideal, especially as they're only just big enough current rating.	
>>> Dis you see my reply Austin?
>>>
>>> Bob
>> 
>> nope.  whole thread seems to be AWOL.  unless it was by email, in which
>> case, you need to fix the address, or it goes into a rarely-checked spambin.
>I replied usenet thus:
>
>"Use your existing stop start overload as the NVR and starter and wire 
>the new box as a latching forward/reverse switch.
>Bob "

ah, right.  Hmmm.

the swtiches in the new box are not latching though.  They're just
push-to-make.  I get the impression it's intended to control something else.

Also, the current switch is not NVR (although that too was cheap), and I'd
prefer it if it was.

I may have to hunt a proper one...
-- 
Austin Shackles.  www.ddol-las.net  my opinions are just that
Travel The Galaxy!  Meet Fascinating Life Forms...
------------------------------------------------\   
   >>  http://www.schlockmercenary.com/  <<      \  ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!

On Tue, 19 Aug 2008 08:22:34 +0100, Austin Shackles
 wrote:

>On or around Mon, 18 Aug 2008 21:46:10 +0100, Bob Minchin
> enlightened us thusly:
>

>>I replied usenet thus:
>>
>>"Use your existing stop start overload as the NVR and starter and wire 
>>the new box as a latching forward/reverse switch.
>>Bob "
>
>ah, right.  Hmmm.
>
>the swtiches in the new box are not latching though.  They're just
>push-to-make.  I get the impression it's intended to control something else.
>
>Also, the current switch is not NVR (although that too was cheap), and I'd
>prefer it if it was.
>
>I may have to hunt a proper one...


Get thee to your nearest electrical wholesaler, plumbing shop or larger DIY
shed and get a DPST or DPDT relay with base, if needed. Use the start button
to energise the coil. One pair of NO contacts to also energise the coil,
giving the latching function and the stop switch in series with those
contacts. The other contacts are now latching on, no-volt release. Total cost
about £5-£8. Use a contactor with auxiliary contacts if the current demands
it.

Mark Rand
RTFM

Austin Shackles wrote:
> On or around Mon, 18 Aug 2008 21:46:10 +0100, Bob Minchin
>  enlightened us thusly:
> 
>> Austin Shackles wrote:
>>> On or around Mon, 18 Aug 2008 18:04:46 +0100, Bob Minchin
>>>  enlightened us thusly:
>>>
>>>> Austin Shackles wrote:
>>>>> I bet this appears twice now.  it seems to be in limbo, so reposting...
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> got cheap on ebay a box with forward reverse stop buttons, but that's all it
>>>>> is, the box and contactors under the buttons.  The start buttons have
>>>>> push-to-make switches and the stop one has push-to-break.
>>>>>
>>>>> So... can I make it drive the single-phase motor on the lathe, forward and
>>>>> reverse, and if so what else does it need.  I already have
>>>>> stop-start-overload switch thing, but that only goes one way.  It's also not
>>>>> no-volt release, which is not ideal.
>>>>>
>>>>> currently, reversing is done with a pair of SPDT switches, which is far from
>>>>> ideal, especially as they're only just big enough current rating.	
>>>> Dis you see my reply Austin?
>>>>
>>>> Bob
>>> nope.  whole thread seems to be AWOL.  unless it was by email, in which
>>> case, you need to fix the address, or it goes into a rarely-checked spambin.
>> I replied usenet thus:
>>
>> "Use your existing stop start overload as the NVR and starter and wire 
>> the new box as a latching forward/reverse switch.
>> Bob "
> 
> ah, right.  Hmmm.
> 
> the swtiches in the new box are not latching though.  They're just
> push-to-make.  I get the impression it's intended to control something else.
> 
> Also, the current switch is not NVR (although that too was cheap), and I'd
> prefer it if it was.
> 
> I may have to hunt a proper one...
  Hi Austin,

Sorry I had made too many assumptions
1 that your existing switch was NVR
2 that the new box had some contactors in behind the buttons

Mark is pointing you in the right direction for the NVR bit but you will 
need a second relay wired to latch the reversing AND most importantly, 
to lockout any change of direction when the motor is running. Single 
phase motors MUST be configured as forward or reverse before starting 
them. Once started, trying to change direction will have no effect.
You might want to consider two start buttons, one for each direction and 
a common stop button. Just make sure you can't operate both start 
buttons at the same time.

HTH

Bob

On or around Tue, 19 Aug 2008 17:31:17 +0100, Bob Minchin
 enlightened us thusly:

>
>Sorry I had made too many assumptions
>1 that your existing switch was NVR
>2 that the new box had some contactors in behind the buttons
>
>Mark is pointing you in the right direction for the NVR bit but you will 
>need a second relay wired to latch the reversing AND most importantly, 
>to lockout any change of direction when the motor is running. Single 
>phase motors MUST be configured as forward or reverse before starting 
>them. Once started, trying to change direction will have no effect.
>You might want to consider two start buttons, one for each direction and 
>a common stop button. Just make sure you can't operate both start 
>buttons at the same time.
>
>HTH
>
>Bob

It might be that I'm not being as precise as I could, either.

The new box has 3 buttons, 2 green and a red in the middle, and it's
designed to be a controller for forward-stop-reverse.  Each button has a
non-latching switch beneath it.  The 2 greens have NO (push-to-make) and the
red in the middle has NC (push-to-break).

If I follow Mark's post right, I can use a DPST relay, with 1 pair of
contacts supplying the motor and self-feeding the coil through the stop
button, while the other terminals switch the motor neutral.

Energise the coil using start button 1, once energised it will stay
energised until the stop is hit, breaking the coil circuit and motor circuit
both.  Lack of supply volts will also release the relay which won't
re-energise by itself until power is supplied by the start button.

All that's good for one direction.

The same circuit wired differently would make the motor go the opposite way
- so either 2 DPST relays or one DPDT provided it has 2 coils, and an "off"
state with nothing connected by default.

The motor could be run from a single giant DPDT switch, provided it was
on-off-on, but this would lack overload and NVR.  

Hmmm.  The existing switch can do the overload bit, and has no NVR.  Might
feed the relays alluded to above from that.



Does that sound right?  nothing so far prevents pressing the "start reverse"
button while the motor's running forward.  Unless a DPDT relay can only have
1 coil energised at a time?

-- 
Austin Shackles.  www.ddol-las.net  my opinions are just that
Travel The Galaxy!  Meet Fascinating Life Forms...
------------------------------------------------\   
   >>  http://www.schlockmercenary.com/  <<      \  ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!

On or around Tue, 19 Aug 2008 19:09:43 +0100, Austin Shackles
 enlightened us thusly:

>
>It might be that I'm not being as precise as I could, either.
>

[snip stuff]

this is more or less what I have:

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=3308521

although naturally at a fraction of the price.

Is what I'm looking for called a "contactor"?  I see plenty of such things,
although I've yet to find a DPDT.  However, I can, AFAICT, do the job with 2
single-way ones.
-- 
Austin Shackles.  www.ddol-las.net  my opinions are just that
Travel The Galaxy!  Meet Fascinating Life Forms...
------------------------------------------------\   
   >>  http://www.schlockmercenary.com/  <<      \  ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!

Austin Shackles wrote:
> On or around Tue, 19 Aug 2008 19:09:43 +0100, Austin Shackles
>  enlightened us thusly:
> 
>> It might be that I'm not being as precise as I could, either.
>>
> 
> [snip stuff]
> 
> this is more or less what I have:
> 
> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=3308521
> 
> although naturally at a fraction of the price.
> 
> Is what I'm looking for called a "contactor"?  I see plenty of such things,
> although I've yet to find a DPDT.  However, I can, AFAICT, do the job with 2
> single-way ones.
Unless the motor is a big bugger then relays ought to do the job and 
these are readily available as change over types. You will need two 
poles to do the main switching and at least one extra pole on each to do 
the 'logic' of the latching and interlock.

Bob

On 19 Aug, 19:09, Austin Shackles
 wrote:
> On or around Tue, 19 Aug 2008 17:31:17 퍝, Bob Minchin
>  enlightened us thusly:
>
SNIP
>
> If I follow Mark's post right, I can use a DPST relay, with 1 pair of
> contacts supplying the motor and self-feeding the coil through the stop
> button, while the other terminals switch the motor neutral.
>
> Energise the coil using start button 1, once energised it will stay
> energised until the stop is hit, breaking the coil circuit and motor circuit
> both.  Lack of supply volts will also release the relay which won't
> re-energise by itself until power is supplied by the start button.
>
> All that's good for one direction.
>
> The same circuit wired differently would make the motor go the opposite way
> - so either 2 DPST relays or one DPDT provided it has 2 coils, and an "off"
> state with nothing connected by default.
>
> The motor could be run from a single giant DPDT switch, provided it was
> on-off-on, but this would lack overload and NVR.  
>
> Hmmm.  The existing switch can do the overload bit, and has no NVR.  Might
> feed the relays alluded to above from that.
>
> Does that sound right?  nothing so far prevents pressing the "start reverse"
> button while the motor's running forward.  Unless a DPDT relay can only have
> 1 coil energised at a time?
>
> --
> Austin Shackles.  www.ddol-las.net my opinions are just that
> Travel The Galaxy!  Meet Fascinating Life Forms...
> ------------------------------------------------\  
>    >>  http://www.schlockmercenary.com/ <<      \  ...and Kill them.
> a webcartoon by Howard Tayler; I like it, maybe you will too!- Hide quoted text -
>
> - Show quoted text -

Austin

No.  That isn't correct.

The neutrals should NOT be switched.

OK.  Assuming you have obtained two mains coil relays with contacts
capable of taking the motor current - remembering that the "start
current" will be higher than the run current - and that you've got
some form of Overload cut-out/Fuse in the mains supply.

For the Start function. Use a double-pole/single-throw (DPST) or doble-
pole/double-throw (DPDT) relay.  Wire one end of the relay coil and
one end of the single-phase motor "Run" winding to Mains Neutral.
Wire one side of the NC Stop switch to Mains live and the other side
to one side of the Start switch.  Wire the other side of the start
switch to the - as yet - unconnected side of the Relay coil.  Connect
one set of the relay NO contacts across the Start button.  Test.
Relay should pull on and hold on operation of the Start button and
drop-out when the Stop button is pressed.

Wire one side of a Tripple Pole/Double-Throw (TPDT) or Quadruple pole/
Double-Throw (QPDT) Relay coil to Mains N.  You could use a contactor
with Main Contacts DPDT and a separate light current "hold contact".
Let's assume we have a TPDT relay.  Wire one side of the Reverse
switch to the junction of the Stop switch and Start switch (previously
wired as above) and the other - as yet - unconnected side to the TPDT
relay coil.  Connect one set of NO contacts of this relay across the
Reverse switch.  Test as above.  Pressing the Reverse button should
energise the TPDT relay which will then hold until the Stop button is
pressed.

OK So far ?

Start Relay to Motor.  Wire one side of the - as yet - unconnected NO
Relay contacts to Main Live.  Wire the other to the - as yet -
unconnected side of the motor "Run Winding"

Reverse Relay to Motor.  Let's call the common of the remaining rwo
sets of contacts C1 and C2 and the NO/NC Contacts as NO1, NO2 and
ditto NC1 & NC2.  Dirstly, wire C1 to one side of the Motor "Start
winding" and C2 to the other side of same.  Connect NO1 ro NC2 and NO2
to NC1.  Connect NO1/NC2 junction to Mains Live and NO2/NC1 junction
to mains neutral.

Operation.  For forward rotation, press Start Button only.  Stop motor
with Stop button.
For reverse rotation, press both Reverse and Start button together.
Stop as above.

Wiring in this way does not require any special circuitry to :-
a) Prevent both Start and Reverse buttons being operated
simultaneously
b) Prevent trying to start the motor in opposite directions
simultaneously (Which would probably mean connecting Mains Live to
Main N - which not a good thing to attempt with a relay contact !)

Downside ?  You need to press two buttons sumultaneously to get
reverse.  So what ?  You'll probably only use reverse very
occasionally.

I hope you can follow this.  If not, I can send you a wiring diagram
if you can ley me know how to send you a PM with attachments (I'm new
to this group and they all use different mechanisms)

Andy

On Tue, 19 Aug 2008 22:16:34 +0100, Bob Minchin 
wrote:

>Austin Shackles wrote:
>> On or around Tue, 19 Aug 2008 19:09:43 +0100, Austin Shackles
>>  enlightened us thusly:
>> 
>>> It might be that I'm not being as precise as I could, either.
>>>
>> 
>> [snip stuff]
>> 
>> this is more or less what I have:
>> 
>> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=3308521
>> 
>> although naturally at a fraction of the price.
>> 
>> Is what I'm looking for called a "contactor"?  I see plenty of such things,
>> although I've yet to find a DPDT.  However, I can, AFAICT, do the job with 2
>> single-way ones.
>Unless the motor is a big bugger then relays ought to do the job and 
>these are readily available as change over types. You will need two 
>poles to do the main switching and at least one extra pole on each to do 
>the 'logic' of the latching and interlock.
>
>Bob

In addition to that, if you wire an NC contact pair of the forward relay in
series with the coil of the reverse relay and vice-versa, then you will avoid
the possibility of both being on at once, with resultant loss of magic smoke.

 With a bit of thought and a lot of sketching, it should be possible to do
this with the double pole(or auxiliary pole on contactors) relays, without
needing the rarity of triple pole devices.

Contactors are basically relays with more robust contacts, usually with a bar
that joins two separate contacts. a bit better for breaking higher currents,
but not necessarily needed for manually operated switching of a domestic
lathe.

Mark Rand
RTFM

On Aug 20, 12:01 am, Mark Rand  wrote:
> On Tue, 19 Aug 2008 22:16:34 퍝, Bob Minchin 
> wrote:
>
>
>
>
>
> >Austin Shackles wrote:
> >> On or around Tue, 19 Aug 2008 19:09:43 퍝, Austin Shackles
> >>  enlightened us thusly:
>
> >>> It might be that I'm not being as precise as I could, either.
>
> >> [snip stuff]
>
> >> this is more or less what I have:
>
> >>http://uk.rs-online.com/web/search/searchBrowseAction.html?method=get> >> although naturally at a fraction of the price.
>
> >> Is what I'm looking for called a "contactor"?  I see plenty of such things,
> >> although I've yet to find a DPDT.  However, I can, AFAICT, do the job with 2
> >> single-way ones.
> >Unless the motor is a big bugger then relays ought to do the job and
> >these are readily available as change over types. You will need two
> >poles to do the main switching and at least one extra pole on each to do
> >the 'logic' of the latching and interlock.
>
> >Bob
>
> In addition to that, if you wire an NC contact pair of the forward relay in
> series with the coil of the reverse relay and vice-versa, then you will avoid
> the possibility of both being on at once, with resultant loss of magic smoke.
>
>  With a bit of thought and a lot of sketching, it should be possible to do
> this with the double pole(or auxiliary pole on contactors) relays, without
> needing the rarity of triple pole devices.
>
> Contactors are basically relays with more robust contacts, usually with a bar
> that joins two separate contacts. a bit better for breaking higher currents,
> but not necessarily needed for manually operated switching of a domestic
> lathe.
>
> Mark Rand
> RTFM- Hide quoted text -
>
> - Show quoted text -

Actually, I should never have attempted to describe the wiring so late
at night.  Mia Culpa.  There's an error.

You need to connect the NO1/NC2 junction to the junction of the Start
relay contact and Motor Run winding. NOT directly to Main L.  That
way, the Start winding is not energised continuously, but only when
the Start relay is operated.

In addition.  You can use 2off DPDT relays for the reversing function
with the coils connected in parallel.  That gives you 4off Change-over
contacts.  Wire the remaing NO contacts across the Start Switch and
you then have single button operation.  Viz.  Press Start (now renamed
Forward) - Motor runs forward.  Press Reverse - Motor Runs Reverse.

Mark. Wrote
"In addition to that, if you wire an NC contact pair of the forward
relay in
series with the coil of the reverse relay and vice-versa, then you
will avoid
the possibility of both being on at once, with resultant loss of magic
smoke."

Not only does that need additional contact sets, but it doesn't matter
if you push the Reverse button as well as the Start.  No smoke will
appear.  The circuit is safe.  In addition, the reverse relay, as I
describe it (modified connexions as above), would de-actuate the start
relay if one of its NC contacts was in series with the start relay
coil, so the motor wouldn't run.

I have the circuitry for using contactors, but you still need
additional relays to do the interlocking - it's still necessary to
swap the conexion of the two ends of the Start Winding wrt the Run
Winding and you can't do that with two DPST contactors.  BTW, the
Interlocking relays also provides the safety operation from covers and
guards micro-switches.

Regards
Andy