end or slow stop circuit for heavy machine motors so that the motors are
able to gradual start stop actions instead of switching ON/OFF
motor and additionally save electricity during the course of actions.
The idea was requested by Mr. Bernard Botte.
Dear mister Swagatam,
Sorry for my english , thanks anyway for any answer you will give
But I also use a planer/thicknesser using a motor rotating at 18000 T/min. It seems made to not
copyrights. Before I had problem I tought it was a motor running at 3000
t/min (2700) multiply by 2 (like others) with a belt to reach a decent
speed of 6000 t/m (5400)
machine smoke and i dismount the machine to isolate the motor to evict
the fire . (the machine was under warranty but i need to make a lot off
look the axis who rotate he seems also shooting on the opposite side of
the gear belt at every start Like there wasn’t a grower . I show the
motor in a company saling different kind of motor.They make also
refurbishing but they explain to me that it was an “exotic” motor but
they set the same diagnostic .Start to fast
system based on BTA 16 800 cw (better than the other mentioned above) it
seems ok but i have only made 3 of them . I’ll want to integrate that
in every big machine . And use only the on/off switch.
on” and one to “switch off” or an on/off switch. But also a
potentiometer to select the minimum level (depending the power of each
motors) when the motor start running and a potentiometer to select the
timing (555) between the slow start and the full speed (maybe also
shortcut the triac with a relay to have full speed an a green led if it
is relevant (but it will be nice) for the switch off the timing maybe
reduce. Why at the end because the extra current and problems binded.
with “fpla” or dedicated processors but I am sure it can also be done
with discrete components.
never study the motors correctly but I know for example that it is not
correct to start the motor with a zero crossing system because It give a
maximum current and that make the same trouble (FIRE!) with the couple
at start and max current …
forum touching other job mechanic wood etc … with no answer and people
say also if it work with a potentiometer but when you change from a
machine to another you can make mistakes etc…
The requested idea of a soft start, soft stop motor switching circuit
can be implemented using a simple triac based dimmer switch concept, as
presented in the following diagrams:
Referring to the above diagrams, the first diagram shows a standard light dimmer or a fan dimmer switch circuit using a heavy duty triac BTA41A/600.
The section which indicates the “4 triac module” is normally occupied
with a potentiometer for enabling a manual speed control adjustment,
wherein a lower resistance adjustment generates higher speed on the fan
motor and vice versa.
In this soft start, soft stop design, this pot section is replaced
with the indicated 4 triac module which can be elaborately visualized in
the second diagram.
Here we see 4 triacs arranged in parallel having 4 individual 220K
resistors at their upper MT1 arm, and 4 individual capacitors at their
gates with different values, and with a sort of sequential order of high
When S1 is switched ON, the triac having the lowest value capacitor
switches ON first, enabling a relatively slow speed start on the motor
due to switching of the relevant 220K resistor at its MT1.
Withing a few millseconds the next subsequent triac conducts which
has the next smaller value, and adds its own 220K resistor in parallel
with the earlier 220K resistor, allowing the motor to gain some more
Identically, the third and the fourth triacs also sequentially switch
ON within the next few milliseconds, thereby adding two more 220K
parallel resistors in the range, which finally allows the motor to reach
its maximum speed.
The above sequential speed increase on the motor allows the motor to
achieve the intended slow start switch ON, as desired by the user.
Quite similarly when the switch S1 is turned OFF, the relevant
capacitors switch OFF in the same order but in a descending manner,
which inhibits the motor from a sudden stop, instead it causes a step
wise slow stop or slow end on its speed.
Feedback from Mr. Bernard:
Dear mister Swag, First of all, thanks for your fast answer. Because you tell me you have a timing problem I have changed my operating system to linux mint 18,1 ‘Serena’ so i haved to re-install all the program I need and test it (setup it!) So apparently everithings seems working OK ! About the first schematic I notice you don’t give any value to the upper side schematics so I pick it up from « How to Make a Simplest Triac Dimmer Switch Circuit »
(C2, C3) C8,C9 = 0.022/250V,
(R1) R9 = 15K,
(R2) R10 = 330K,
(R3) R11 = 33K,
(R4) R12 = 100 Ohms,
Diac = DB3,
Triac = BT136 => BTA41 600
L1 = 40uH
About the second schematic so simple solution i never have dreamed !!! to be tested asap Genial! we say in French. I doesn’t know that you can use polarized condensators for such AC applications! And also that 50 volt was suffisant ! I you have a moment to explain why - Anyway maybe i’ll try it this weekend if i have all the component. I prefer use new capacitors my stock never change since 1993! In fact i was trying different ways using for exemple opto triac (MOC) but i also need to pick the freq of the AC network, also another based on your schematic Kiln Temperature Controller Circuit but with up down counter 4516b and 555 etc,etc so complicated Many thanks Regards B.botte
attached properly and therefore it was not showing, but I have corrected
it now and have posted it back in the article.
68K resistor which will drop the current significantly and not allow
the capacitors to burn, this is my understanding.
with a DC drive, but yes you are right, in order to make it DC for the
capacitors we need to add a 1N4007 in series with the gate 1K resistors.
operate very smoothly or fails to produce the expected results, we could
modify the existing gate drive for the 4 triacs into optocoupler based
drivers, and perform the same sequential delayed switching but through
an external DC circuit.