G
Gerhard v d Berg
Simple reversible motor control circuit for curtains (drapes)
(AGvdBerg 2005-05-26)
I searched for simple circuits but could not find any so I decided to
post these, as there seem to be lots of interest.
These are very simple circuits that do not require extra electronic
components such as gates, timers, transistors and smoothing capacitors
or regulators. However nothing prevents one from enhancing the circuits
by adding remote control and PWM (Pulse Width Modulation) to the
basic circuits below.
Circuit 1: Curtain (Drape) motor direction control with automatic stop
Stop1 Stop2
Open & Close can be substituted Left |<------------->| Right
for Left & Right
/ \
/<|LS1 LS2|>\
Transformer / | | \
|--------+------------| |--+-o |-+---------+-| \-+--|
|--| | | DPDT | | | | | | |
--- | | | | SW1a | | +--|>|--+ +--|<|--+ |
) | | /\+ |-(-----o /o-| | D1 (3A) D2 (3A) |
)( | / \ | | |===/ | -------+
AC )( |_/ DB \_~ | | H | o--------| | __|__
)( ~ \ 3A / | | | H=| L<-->R | / DC
\
)( \ / | | | H | o--------| C1 ===
|Motor|
) | \/- | | | |===\ | |
\_____/
--- | __ | | | +-----o \o-| | | |
|-__---(----| | SW1b | | -------+
Fuse 3A| | | | |
|-------+--------------| |-------------------------------|
(cut & paste to Notepad for fixed pitch font viewing)
All diodes should be selected to survive the motor's stall current!
The fuse should preferably be the slow blow type and rated a bit
less than the diodes.
Operation:
The Open/Close switch (SW1) (DPDT Double Pole Double Through)
selects the voltage polarity applied to the motor and thus motor
direction to open or close curtains (drapes).
If the mechanism is not at either of the limits, the Limit Switches
(LS1 & LS2) will be closed. Depending on the position of SW1 and
motor connections, the motor will turn clockwise or anti-clockwise
to open or close the curtains (drapes).
When the curtains (drapes) approach either the final open or closed
positions, an adjustable limit switch catch should open the contacts
of the appropriate limit switch (LS1 or LS2) and stop the current
flow and thus the motor and movement of the curtains (drapes).
At this point the diode across the open limit switch contacts should
be reverse biased and thus not conduct.
If the Open/Close switch (SW1) is switched in the opposite direction
the voltage polarity across the motor would be reversed and the
diode
should now conduct until curtain mechanism moves and the now open
limit switch closes again. The current will continue to flow until
the opposite limit switch is reached opens to interrupt the current
flow and stop the motor. A special switch with a Centre-OFF position
could be used for (SW1) or a separate Power ON/OFF switched (not in
the drawing) will allow the curtains (drapes) to be partly drawn.
The transformer, diodes, fuse and switches should be selected
according to the requirements of the specific motor and curtain
(drape)
mechanism. Capacitor C1 suppresses the electrical noise generated by
the motor.
For every installation the power required to move the mechanics
can be different (due to the type of curtains and friction and often
the power supplied to the motor might require some tuning.
During installation and setup the use of a Variac or light dimmer to
slowly increase the power to the circuit is highly recommended.
This allows one to verify the correct setting of the limit switches
and fine-tune the circuit (transformer) voltage. It also assists
with
the selection of the appropriate resistors for the speed-reduction
switches as the mechanism approaches the limit switches
(see circuit 2).
A transformer with extra taps just below and above the normally
required output voltage, can be quite handy, else an appropriate
dropper resistor can be employed to reduce the power to the motor
as required.
The rectified but un-smoothed AC voltage supplies a pulsating DC
voltage and current to the motor that helps to overcome friction
in the curtain drape mechanism (and assists starting) but reduces
the average voltage applied to the motor. The rectified AC voltage
pulses should also be less strenuous to switch contacts than pure
DC.
Circuit 2: Curtain (Drape) motor control with automatic stop.
The circuit also includes extra switches to reduce motor speed
just before the end-of-rail limit switch is reached.
This circuit only supplies half-wave power to the motor but
employs a simple SPDT (Single Pole Double Through) switch
for direction control. A higher voltage supply transformer is
however required to compensate.
The full-wave power supply with DPDT switch depicted in circuit 1
could however be used with the rest of the circuit.
Stop1 Slow1 FAST Slow2 Stop2
Left |<_________---------------__________>| Right
Right
--> / / \ \
D3 /<|LS1 /<|LS2 LS3|>\ LS4|>\
SW /o--|>|-| / | / | | \ | \
|--o/ +--+/ |+--+-/ |-+----------+-| \-+--+| \+---|
| o--|<|-| | | | | | | | | |
| D4 +-|>|-+ +-/\/\/-+ +-/\/\/-+ +-|<|-+ |
--- | <-- D1 R1 R2 D2 |
) | Left -------+
)( | __|__
AC )( Transformer Open & Close can be substituted | / DC \
)( for Left & Right C1 === |Motor|
) | | \_____/
) | | |
--- | -------+
| _______ Fuse 3A (see description) |
|------------|_______|-------------------------------------------|
All diodes should be selected to survive the motor's stall current.
R1 & R2 values are determined by experimentation - should be high
wattage.
These basic circuits could be used for more than curtains (drapes)
and the pulsed AC lends itself to SCR and Triac control.
Have Fun!!!!
Gerhard van den Berg
-=OOO=-
(AGvdBerg 2005-05-26)
I searched for simple circuits but could not find any so I decided to
post these, as there seem to be lots of interest.
These are very simple circuits that do not require extra electronic
components such as gates, timers, transistors and smoothing capacitors
or regulators. However nothing prevents one from enhancing the circuits
by adding remote control and PWM (Pulse Width Modulation) to the
basic circuits below.
Circuit 1: Curtain (Drape) motor direction control with automatic stop
Stop1 Stop2
Open & Close can be substituted Left |<------------->| Right
for Left & Right
/ \
/<|LS1 LS2|>\
Transformer / | | \
|--------+------------| |--+-o |-+---------+-| \-+--|
|--| | | DPDT | | | | | | |
--- | | | | SW1a | | +--|>|--+ +--|<|--+ |
) | | /\+ |-(-----o /o-| | D1 (3A) D2 (3A) |
)( | / \ | | |===/ | -------+
AC )( |_/ DB \_~ | | H | o--------| | __|__
)( ~ \ 3A / | | | H=| L<-->R | / DC
\
)( \ / | | | H | o--------| C1 ===
|Motor|
) | \/- | | | |===\ | |
\_____/
--- | __ | | | +-----o \o-| | | |
|-__---(----| | SW1b | | -------+
Fuse 3A| | | | |
|-------+--------------| |-------------------------------|
(cut & paste to Notepad for fixed pitch font viewing)
All diodes should be selected to survive the motor's stall current!
The fuse should preferably be the slow blow type and rated a bit
less than the diodes.
Operation:
The Open/Close switch (SW1) (DPDT Double Pole Double Through)
selects the voltage polarity applied to the motor and thus motor
direction to open or close curtains (drapes).
If the mechanism is not at either of the limits, the Limit Switches
(LS1 & LS2) will be closed. Depending on the position of SW1 and
motor connections, the motor will turn clockwise or anti-clockwise
to open or close the curtains (drapes).
When the curtains (drapes) approach either the final open or closed
positions, an adjustable limit switch catch should open the contacts
of the appropriate limit switch (LS1 or LS2) and stop the current
flow and thus the motor and movement of the curtains (drapes).
At this point the diode across the open limit switch contacts should
be reverse biased and thus not conduct.
If the Open/Close switch (SW1) is switched in the opposite direction
the voltage polarity across the motor would be reversed and the
diode
should now conduct until curtain mechanism moves and the now open
limit switch closes again. The current will continue to flow until
the opposite limit switch is reached opens to interrupt the current
flow and stop the motor. A special switch with a Centre-OFF position
could be used for (SW1) or a separate Power ON/OFF switched (not in
the drawing) will allow the curtains (drapes) to be partly drawn.
The transformer, diodes, fuse and switches should be selected
according to the requirements of the specific motor and curtain
(drape)
mechanism. Capacitor C1 suppresses the electrical noise generated by
the motor.
For every installation the power required to move the mechanics
can be different (due to the type of curtains and friction and often
the power supplied to the motor might require some tuning.
During installation and setup the use of a Variac or light dimmer to
slowly increase the power to the circuit is highly recommended.
This allows one to verify the correct setting of the limit switches
and fine-tune the circuit (transformer) voltage. It also assists
with
the selection of the appropriate resistors for the speed-reduction
switches as the mechanism approaches the limit switches
(see circuit 2).
A transformer with extra taps just below and above the normally
required output voltage, can be quite handy, else an appropriate
dropper resistor can be employed to reduce the power to the motor
as required.
The rectified but un-smoothed AC voltage supplies a pulsating DC
voltage and current to the motor that helps to overcome friction
in the curtain drape mechanism (and assists starting) but reduces
the average voltage applied to the motor. The rectified AC voltage
pulses should also be less strenuous to switch contacts than pure
DC.
Circuit 2: Curtain (Drape) motor control with automatic stop.
The circuit also includes extra switches to reduce motor speed
just before the end-of-rail limit switch is reached.
This circuit only supplies half-wave power to the motor but
employs a simple SPDT (Single Pole Double Through) switch
for direction control. A higher voltage supply transformer is
however required to compensate.
The full-wave power supply with DPDT switch depicted in circuit 1
could however be used with the rest of the circuit.
Stop1 Slow1 FAST Slow2 Stop2
Left |<_________---------------__________>| Right
Right
--> / / \ \
D3 /<|LS1 /<|LS2 LS3|>\ LS4|>\
SW /o--|>|-| / | / | | \ | \
|--o/ +--+/ |+--+-/ |-+----------+-| \-+--+| \+---|
| o--|<|-| | | | | | | | | |
| D4 +-|>|-+ +-/\/\/-+ +-/\/\/-+ +-|<|-+ |
--- | <-- D1 R1 R2 D2 |
) | Left -------+
)( | __|__
AC )( Transformer Open & Close can be substituted | / DC \
)( for Left & Right C1 === |Motor|
) | | \_____/
) | | |
--- | -------+
| _______ Fuse 3A (see description) |
|------------|_______|-------------------------------------------|
All diodes should be selected to survive the motor's stall current.
R1 & R2 values are determined by experimentation - should be high
wattage.
These basic circuits could be used for more than curtains (drapes)
and the pulsed AC lends itself to SCR and Triac control.
Have Fun!!!!
Gerhard van den Berg
-=OOO=-
