Forklift truck circuit

A

Adrian Tuddenham

Guest
Does anyone happen to have the circuit diagram for a Lansing R16
forklift truck? I've been asked to find an intermittent fault in the
traction motor control circuit.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote in message
news:1k4951n.1tn34yhz62dmiN%adrian@poppyrecords.invalid.invalid...
Does anyone happen to have the circuit diagram for a Lansing R16
forklift truck? I've been asked to find an intermittent fault in the
traction motor control circuit.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Click to expand...


I know someone in the repair side of their UK operation if you could get
more on the symptoms, I'm assuming no schematic would be available ,
external to the co. I only see him weekends.
 
N_Cook <diverse@tcp.co.uk> wrote:

Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote in message
news:1k4951n.1tn34yhz62dmiN%adrian@poppyrecords.invalid.invalid...
Does anyone happen to have the circuit diagram for a Lansing R16
forklift truck? I've been asked to find an intermittent fault in the
traction motor control circuit.
[...]
I know someone in the repair side of their UK operation if you could get
more on the symptoms, I'm assuming no schematic would be available ,
external to the co. I only see him weekends.
Click to expand...
The hydraulics and their associated electrics appear to work properly
but the traction system became intermittent and has now failed
altogether. The relays on the electronic control board are working in
response to the foot pedals, but the main traction power contactors on
the +ve busbar do not operate. The contactors will operate when power
is applied directly to their operating coils, but still the thyristors
don't switch on.

I have already found several potential problems, including intermittent
connections in the 50-way ribbon cable to the electronics board. A
proper circuit diagram would be so helpful for tracing the path of the
non-working circuits.

Any help would be much appreciated

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
On 11/07/2011 18:09, Adrian Tuddenham wrote:
Does anyone happen to have the circuit diagram for a Lansing R16
forklift truck? I've been asked to find an intermittent fault in the
traction motor control circuit.
Click to expand...
Be careful with these things.

German Forklift Training Video (funny)
http://www.youtube.com/watch?v=Tqd4aPs5WTA

It may be bit slow at the start. Jump about 2mins in and the sick mayhem
starts...

;-)

--
Adrian C
 
Adrian C <email@here.invalid> wrote:

On 11/07/2011 18:09, Adrian Tuddenham wrote: > Does anyone happen to
have the circuit diagram for a Lansing R16 > forklift truck? I've
been asked to find an intermittent fault in the > traction motor control
circuit.

Be careful with these things.

German Forklift Training Video (funny)
http://www.youtube.com/watch?v=Tqd4aPs5WTA
Click to expand...
Thanks for that, you've really cheered me up :-(

I was already being very cautious. Before I did anything I measured the
battery voltage: 48v, and had a look at the main fuse: 500 A, - and
worked out that one slip of the spanner could involve me in a lot of
very hot metal.

It weighs about 4 tonnes, so I'm also very aware of what might happen if
the speed contoller chopper circuits turn out to have have failed S/C
and I accidentally close the motor contactor.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
N_Cook <diverse@tcp.co.uk> wrote:

Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote in message
news:1k4951n.1tn34yhz62dmiN%adrian@poppyrecords.invalid.invalid...
Does anyone happen to have the circuit diagram for a Lansing R16
forklift truck? I've been asked to find an intermittent fault in the
traction motor control circuit.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk



I know someone in the repair side of their UK operation if you could get
more on the symptoms, I'm assuming no schematic would be available ,
external to the co. I only see him weekends.
Click to expand...
I've now managed to borrow the service manual. Although it doesn't give
a full circuit diagram, it gives individual diagrams of the
sub-sections, so I ought to be able to work out what is going on (or
failing to go on).

Thanks for offering to help.



--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
On Thu, 14 Jul 2011 13:56:47 +0100,
adrian@poppyrecords.invalid.invalid (Adrian Tuddenham) wrote:

Adrian C <email@here.invalid> wrote:

On 11/07/2011 18:09, Adrian Tuddenham wrote: > Does anyone happen to
have the circuit diagram for a Lansing R16 > forklift truck? I've
been asked to find an intermittent fault in the > traction motor control
circuit.

Be careful with these things.

German Forklift Training Video (funny)
http://www.youtube.com/watch?v=Tqd4aPs5WTA

Thanks for that, you've really cheered me up :-(

I was already being very cautious. Before I did anything I measured the
battery voltage: 48v, and had a look at the main fuse: 500 A, - and
worked out that one slip of the spanner could involve me in a lot of
very hot metal.

It weighs about 4 tonnes, so I'm also very aware of what might happen if
the speed contoller chopper circuits turn out to have have failed S/C
and I accidentally close the motor contactor.
Click to expand...
Have you verified that the motor brushes are in good order and
properly bedded ?
 
Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote in message
news:1k4gykd.4scwxboojc8uN%adrian@poppyrecords.invalid.invalid...
N_Cook <diverse@tcp.co.uk> wrote:

Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote in message
news:1k4951n.1tn34yhz62dmiN%adrian@poppyrecords.invalid.invalid...
Does anyone happen to have the circuit diagram for a Lansing R16
forklift truck? I've been asked to find an intermittent fault in
the
traction motor control circuit.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk



I know someone in the repair side of their UK operation if you could get
more on the symptoms, I'm assuming no schematic would be available ,
external to the co. I only see him weekends.

I've now managed to borrow the service manual. Although it doesn't give
a full circuit diagram, it gives individual diagrams of the
sub-sections, so I ought to be able to work out what is going on (or
failing to go on).

Thanks for offering to help.



--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Click to expand...

he's on his hols this week as it happens.
 
HW-K <Henri@bigpond.com> wrote:

On Thu, 14 Jul 2011 13:56:47 +0100,
adrian@poppyrecords.invalid.invalid (Adrian Tuddenham) wrote:

Adrian C <email@here.invalid> wrote:

On 11/07/2011 18:09, Adrian Tuddenham wrote: > Does anyone happen to
have the circuit diagram for a Lansing R16 > forklift truck? I've
been asked to find an intermittent fault in the > traction motor control
circuit.

Be careful with these things.

German Forklift Training Video (funny)
http://www.youtube.com/watch?v=Tqd4aPs5WTA

Thanks for that, you've really cheered me up :-(

I was already being very cautious. Before I did anything I measured the
battery voltage: 48v, and had a look at the main fuse: 500 A, - and
worked out that one slip of the spanner could involve me in a lot of
very hot metal.

It weighs about 4 tonnes, so I'm also very aware of what might happen if
the speed contoller chopper circuits turn out to have have failed S/C
and I accidentally close the motor contactor.

Have you verified that the motor brushes are in good order and
properly bedded ?
Click to expand...
Not yet. I haven't even succeeded in getting the motor contactor to
close.

There are a few stray wires that need putting back in their correct
places before I can do anything more. The circuit incorporates lots of
interlocks which won't allow anything to operate if there is a fault in
the poower control gear.

The manual (which I have now been able to borrow) says that the wheels
ought to be jacked clear of the floor before testing the traction
circuits. The electronics problem has temporarily become a background
issue and some heavy engineering is now required (the truck weighs 4
tonnes).


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
On Sun, 17 Jul 2011 09:31:42 +0100,
adrian@poppyrecords.invalid.invalid (Adrian Tuddenham) wrote:

HW-K <Henri@bigpond.com> wrote:

On Thu, 14 Jul 2011 13:56:47 +0100,
adrian@poppyrecords.invalid.invalid (Adrian Tuddenham) wrote:

Adrian C <email@here.invalid> wrote:

On 11/07/2011 18:09, Adrian Tuddenham wrote: > Does anyone happen to
have the circuit diagram for a Lansing R16 > forklift truck? I've
been asked to find an intermittent fault in the > traction motor control
circuit.

Be careful with these things.

German Forklift Training Video (funny)
http://www.youtube.com/watch?v=Tqd4aPs5WTA

Thanks for that, you've really cheered me up :-(

I was already being very cautious. Before I did anything I measured the
battery voltage: 48v, and had a look at the main fuse: 500 A, - and
worked out that one slip of the spanner could involve me in a lot of
very hot metal.

It weighs about 4 tonnes, so I'm also very aware of what might happen if
the speed contoller chopper circuits turn out to have have failed S/C
and I accidentally close the motor contactor.

Have you verified that the motor brushes are in good order and
properly bedded ?

Not yet. I haven't even succeeded in getting the motor contactor to
close.

There are a few stray wires that need putting back in their correct
places before I can do anything more. The circuit incorporates lots of
interlocks which won't allow anything to operate if there is a fault in
the poower control gear.

The manual (which I have now been able to borrow) says that the wheels
ought to be jacked clear of the floor before testing the traction
circuits. The electronics problem has temporarily become a background
issue and some heavy engineering is now required (the truck weighs 4
tonnes).
Click to expand...
Step 1:
Is the machine located on level ground/floor ?

Chock front wheels to prevent rolling forward.

Step 2:
Use suitable vehicle jacks to lift drive wheel approx 30 mm clear of
floor.

Two robust car jacks placed strategically would probably suffice.

Place suitable wood or metal supports under chassis adjacent to drv
wheel.

Remove jack/jacks.

Step 3:
With battery disconnected inspect drv mtr commutator and brushes
integrity.

Other considerations can now be safely assessed, including command
logic manual and closure of drv contactor at lowest speed selection.
( i.e. no fwd or rev command input)

HTH
 
HW-K <Henri@bigpond.com> wrote:

On Sun, 17 Jul 2011 09:31:42 +0100, adrian@poppyrecords.invalid.invalid
(Adrian Tuddenham) wrote:

HW-K <Henri@bigpond.com> wrote:

On Thu, 14 Jul 2011 13:56:47 +0100,
adrian@poppyrecords.invalid.invalid (Adrian Tuddenham) wrote:

Adrian C <email@here.invalid> wrote:

On 11/07/2011 18:09, Adrian Tuddenham wrote: > Does anyone happen
to have the circuit diagram for a Lansing R16 > forklift truck?
I've been asked to find an intermittent fault in the > traction
motor control circuit.
Click to expand...
[...]

It weighs about 4 tonnes, so I'm also very aware of what might
happen if the speed contoller chopper circuits turn out to have have
failed S/C and I accidentally close the motor contactor.

Have you verified that the motor brushes are in good order and
properly bedded ?
Click to expand...
[...]

Step 1: Is the machine located on level ground/floor ?
Click to expand...
It is now - after using my car to bulldoze it into the warehouse. (We
couldn't get it to move at first, then discovered that the hydraulics
had run down and allowed the fork tines to dig into the tarmac.)

Chock front wheels to prevent rolling forward.

Step 2: Use suitable vehicle jacks to lift drive wheel approx 30 mm
clear of floor.
Two robust car jacks placed strategically would probably suffice.
Click to expand...
My car jack had insufficient lifting capacity. We used a length of
steel joist as a lever to increase the lifting capacity of the jack, one
side at a time. Even with the handbrake firmly on, the machine
over-rode its chocks at the first attempt and we had to re-position the
lever. No damage resulted because we had anticipated that possibility
and had taken suitable precaustions.

Place suitable wood or metal supports under chassis adjacent to drv
wheel.
Click to expand...
And build up wooden blocks under outer sides of machine to give greater
stability.


Remove jack/jacks.

Step 3: With battery disconnected inspect drv mtr commutator and brushes
integrity.
Click to expand...
In-wheel motors with integral gearbox, very difficult to inspect. We
temporarily ignored this step as there had been no indication of motor
trouble (the machine had two motors and it was unlikely that both had
failed simultaneously).

Other considerations can now be safely assessed, including command logic
manual and closure of drv contactor at lowest speed selection. ( i.e. no
fwd or rev command input)
Click to expand...
Broken microswitch replaced in speed controller.
Supply wire to 'direction' contactors replaced onto correct PCB tag.

All relays and contactors now operating, but the thyristors are not
being triggered. Injecting a small amount of noise into the base of the
drive transistor of the 'ON' thyristor will trigger the thyristor; then
both wheel motors run for a moment before the 'direction' contactor
opens and kills the circuit.

That ilustrates one of the safety features of this machine: the
'direction' contactor is fed from a reservoir capacitor which is fed
via. a diode from the anode of the 'ON' thyristor. If the 'ON'
thyristor stays conducting for too long, the contactor drops out. As
long as normal ON/OFF commutation takes place, the contactor will stay
in.

The conclusion is that neither the 'ON' nor the 'OFF' thyristor is being
triggered properly. I have traced the circuit of their drive stages
and run the board up on a bench supply; both drivers appear to be
working satisfactorily but are not receiving any triggering signals from
the timing circuit.

So far, I have not yet managed to fathom the timing circuit. According
to the manual it is a closed-loop system which monitors the motor
current and the 'throttle' position. A small three-limbed saturable
reactor forms the basis of the sensor system. The centre limb carries a
coil whose inductance controls the timing circuit; one outer limb is
gapped and closed by a permananet magnet on the throttle shaft; the
other outer limb is magnetically coupled to the motor supply cable.

At low throttle settings. the magnet saturates the centre limb, the coil
inductance is low and the motor 'ON' pulses are short. As the throttle
pedal is depressed, the magnet is withdrawn, reducing saturation and
causing the inductance of the centre limb to increase. This lengthens
the 'ON' pulses until the increase of motor current returns the
saturation to a median value. At full throttle, after the motor has
attained full speed, neither the magnet nor the motor current is
sufficient to give saturation, the inductance is high and the 'ON'
pulses reach their maximum length.

I have not yet discovered how the inductance is detected and used to
control the timing of the pulses. It is a simple two-wire circuit and
the coil resistance at DC reads 4 ohms (the manual doesn't indicate what
value it should be).


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
On Tue, 19 Jul 2011 09:33:50 +0100,
adrian@poppyrecords.invalid.invalid (Adrian Tuddenham) wrote:


That ilustrates one of the safety features of this machine: the
'direction' contactor is fed from a reservoir capacitor which is fed
via. a diode from the anode of the 'ON' thyristor. If the 'ON'
thyristor stays conducting for too long, the contactor drops out. As
long as normal ON/OFF commutation takes place, the contactor will stay
in.

The conclusion is that neither the 'ON' nor the 'OFF' thyristor is being
triggered properly. I have traced the circuit of their drive stages
and run the board up on a bench supply; both drivers appear to be
working satisfactorily but are not receiving any triggering signals from
the timing circuit.

So far, I have not yet managed to fathom the timing circuit. According
to the manual it is a closed-loop system which monitors the motor
current and the 'throttle' position. A small three-limbed saturable
reactor forms the basis of the sensor system. The centre limb carries a
coil whose inductance controls the timing circuit; one outer limb is
gapped and closed by a permananet magnet on the throttle shaft; the
other outer limb is magnetically coupled to the motor supply cable.

At low throttle settings. the magnet saturates the centre limb, the coil
inductance is low and the motor 'ON' pulses are short. As the throttle
pedal is depressed, the magnet is withdrawn, reducing saturation and
causing the inductance of the centre limb to increase. This lengthens
the 'ON' pulses until the increase of motor current returns the
saturation to a median value. At full throttle, after the motor has
attained full speed, neither the magnet nor the motor current is
sufficient to give saturation, the inductance is high and the 'ON'
pulses reach their maximum length.

I have not yet discovered how the inductance is detected and used to
control the timing of the pulses. It is a simple two-wire circuit and
the coil resistance at DC reads 4 ohms (the manual doesn't indicate what
value it should be).
Click to expand...

FYI.

Title:
CONTROL SYSTEMS FOR ELECTRIC MOTORS

United States Patent 3562616

Abstract:
A motor drive circuit in which a direct current motor is fed with
pulses of current by means of a controlled rectifier connected as a
power switch between a power source and the motor. The conduction of
the rectifier is controlled by a potential divider one element of
which is a flux-responsive resistor adjacent a conductor of armature
current. The divider is energized with a constant voltage thereby
avoiding use of a free-running pulse generator as a source of trigger
pulses for the rectifier. A coil adjacent the resistor provides
additional flux through the resistor for controlling the pulse rate of
the motor.

http://www.freepatentsonline.com/3562616.html

http://www.freepatentsonline.com/3562616.pdf

regards
 
HW-K <Henri@bigpond.com> wrote:

On Tue, 19 Jul 2011 09:33:50 +0100,
adrian@poppyrecords.invalid.invalid (Adrian Tuddenham) wrote:


That ilustrates one of the safety features of this machine: the
'direction' contactor is fed from a reservoir capacitor which is fed
via. a diode from the anode of the 'ON' thyristor. If the 'ON'
thyristor stays conducting for too long, the contactor drops out. As
long as normal ON/OFF commutation takes place, the contactor will stay
in.

The conclusion is that neither the 'ON' nor the 'OFF' thyristor is being
triggered properly. I have traced the circuit of their drive stages
and run the board up on a bench supply; both drivers appear to be
working satisfactorily but are not receiving any triggering signals from
the timing circuit.

So far, I have not yet managed to fathom the timing circuit. According
to the manual it is a closed-loop system which monitors the motor
current and the 'throttle' position. A small three-limbed saturable
reactor forms the basis of the sensor system. The centre limb carries a
coil whose inductance controls the timing circuit; one outer limb is
gapped and closed by a permananet magnet on the throttle shaft; the
other outer limb is magnetically coupled to the motor supply cable.

At low throttle settings. the magnet saturates the centre limb, the coil
inductance is low and the motor 'ON' pulses are short. As the throttle
pedal is depressed, the magnet is withdrawn, reducing saturation and
causing the inductance of the centre limb to increase. This lengthens
the 'ON' pulses until the increase of motor current returns the
saturation to a median value. At full throttle, after the motor has
attained full speed, neither the magnet nor the motor current is
sufficient to give saturation, the inductance is high and the 'ON'
pulses reach their maximum length.

I have not yet discovered how the inductance is detected and used to
control the timing of the pulses. It is a simple two-wire circuit and
the coil resistance at DC reads 4 ohms (the manual doesn't indicate what
value it should be).


FYI.

Title:
CONTROL SYSTEMS FOR ELECTRIC MOTORS

United States Patent 3562616

Abstract:
A motor drive circuit in which a direct current motor is fed with
pulses of current by means of a controlled rectifier connected as a
power switch between a power source and the motor. The conduction of
the rectifier is controlled by a potential divider one element of
which is a flux-responsive resistor adjacent a conductor of armature
current. The divider is energized with a constant voltage thereby
avoiding use of a free-running pulse generator as a source of trigger
pulses for the rectifier. A coil adjacent the resistor provides
additional flux through the resistor for controlling the pulse rate of
the motor.

http://www.freepatentsonline.com/3562616.html

http://www.freepatentsonline.com/3562616.pdf
Click to expand...
Very similar, but it doesn't use a saturable reactor to sense the motor
current.

My problem was the detail of the electronics which sensed the change in
inductance due to saturation. I still haven't fathomed it; but whilst
following the circuit I found a S/C transistor and replaced it. The
board suddenly burst into life, so I put it back in the truck and
everything is working properly again.

The truck owner is happy - thanks to everyone who helped.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
 
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