VFD's and 3phase Induction motors FAQ corner / pls. Read all first

One simple reason.... You can program it for one model... then that's it... you need to do completely new program for each servo motor driver, although they use modbus, as they use different internal values and commands. Then its the testing, who can afford to purchase create control program for and test all these thousands of different servo drives?

@tronicgr I am one of the people who appreciate geeks, nerds and other out of the box thinkers.... for who they are and what they have brought us to date!
This might be of thread and to social....

@tronicgr I get your point but maybe there is away to boldly go where no one has gone before? With preferred drives that, with some remapping done by a geek or the "geeks united group", can be integrated into the sim community as the next level up?

@Martin van Hagen , Several members here like using the Pololu Jrk 12v2 because they think the pid control on them is outstanding! But by doing so, they limit themselves on the amount of motor power they can use. I personally use Dimension Engineering's Sabertooth 2x60 motor controllers. They are 60 amps continuous with peaks of 120amps. A 400watt motor at 12vdc is rated at around 34 watts so the 2x60 is more than capable. I run considerably larger motors than that with my rig but a lot of your power requirements will depend on you rigs design. Even though you can't use a jrk with that large of a motor, you can use an arduino with pid code on it and a sabertooth 2x60. One sabertooth will control two motors. It will control them directly from the arduino too without the need of external dac's, op-amps, etc.
Oh! Did I forget to mention no threat of electrocution either! Lol.

Me too @tronicgr . But so far I haven’t seen any evidence from you to back up your facts even though I’ve asked, that’s all. It’s more convincing when others don’t have to take just one persons word alone for truth!

I agree that the school of hard knocks is a good one! But again, I’m just asking you to back up your statements with provable facts so there is not as much doubt about AC vs DC power.

I don’t doubt you believe AC is better! I’m just asking for evidence as to why you say an AC motor is more powerful than a DC motor. The white paper on AC and DC motor comparisons I posted has pros and cons for both types and there are arguments to be made about AC having more torque under certain circumstances. But if you won't attempt to prove your “facts" yourself, I’m not going to do it for you.

One thing though, with high voltage AC, even an electrician usually turns off the power before they wire something so they don’t electrocute themselves accidentally! If there weren’t the possibility of fire or death, the government couldn’t use that excuse to make us get a permit and claim it’s for our own safety. While I don’t know about everybody else’s neck of the woods, where I live, you don’t need an electrician or a permit to work with low voltage DC power. Why? It is not hazardous in the since AC voltage is!

True on that @BlazinH , I use JRKS for that reason, I am code hopeless. I would have to rely on other for code writing, so I restricted to motor size.
Still a good 2 DOF seat mover full frame can be built.
The only 3DOF frame jrks dc motors was Aldoz sim, and he has since gone from here.
The work you have done with larger DC motors is certainly commendable an I admire that work.

I too would be interested in this solution, and I would be willing to try a few different models out if anyone can recommend some. I can do coding on the arduino, and have some experience with standard VSD's. I would like to try and work on this soon myself, so if there's a "geeks united group", I'm in!

Its too expensive for anyone here to use real servo motors...

Hmm... evidence? back up what facts?

I don't remember mentioning ever to wire anything that has 220v while its attached on live circuit... are you crazy? the electrician has to wire everything until the circuit breaker... then after you are done connecting the power cord on the VFD inverters (or plug in your computer, or plug in your cellphone, or plug in your TV, or plugin in your shaver etc) and THEN you can turn on the power!!!!!!! lol... why its hard to understand?

And as far as I remember, I was always using a large switch between the car battery and the h-bridge, on my joyrider, to turn OFF the power while working on the wiring or the frame. I wouldn't want the platform to start moving and cut my fingers... So what's your point?

I see posts fly by about safety of electricity and the fear of getting zapped. Well if you look around the house from a safety point of view there are often more dangerous situations in your every day life waiting for you to get seriously injured than you would get killed by electricity. We should remember that any installation concerning electricity should be done with care and knowledge of the subject. So if the AC voltage is above 52Volts it could be lethal but also 12oVdc and beyond would make you exit the gene pool. Basically we should respect the regulations of the country we are "operating" our simulators. Often a domestic distribution board is protected by a differential protection relay that guards over the current coming in the house and going out via the neutral. If there is a difference of 30mA it just disconnects the supply going into your house or part of the house after the protection relay. This should be sufficient to "bite" you but not kill you, so you know for the next time to isolate your simulator. So if all your life connections can not be touched (IP22) and all metal parts are correctly earthed then 230Vac is safe to use and electrocution will be impossible.... the danger is hidden in the poor workmanship and often the eagerness in fixing something while the power is on or waiting for the VFD to discharge...
As @tronicgr correctly mentioned "to turn OFF the power while working on the wiring or the frame. I wouldn't want the platform to start moving and cut my fingers...." is the safest way of fixing things in both voltages.What i like about 230Vac is the instant amount of power available form just a domestic outlet in NL = 3680W (or BR = 4400W where I live 6 months of the year). Try to squeeze that out of your "DC bus" and if you do then make sure you have it all properly protected through gutsy fuses and isolation switches etc. As we say in my industry "safety first"!

Never mind!

Yes, life is filled with dangers! The bottom line is if you are comfortable using high voltage AC then use it. But this is a dif forum so its not wise imho to recommend using AC without warning of its dangers! Even with warnings, I wouldn’t feel very good if someone inexperienced in the use of 220vac used it on my recommendation and then injures or kill themselves or others because of it! Here in the US, we don’t use ground fault interrupters (GFI) on 220vac. 220vac is generally only used for electric stoves and ovens, electric dryers, and heat and air here in homes, and the rest is 110vac. We mostly only use GFI’s with 110vac for outlets in areas where water or moisture can be present like bathrooms, kitchens, and exterior outlets.

So I have been attempting to inform others that it is not absolutely necessary to use AC if you want to use larger motors such as 1hp for example. AC does have a definite advantage in the fact that it is already available in most of our homes in a somewhat high voltage. Maybe 120vdc is dangerous too, but since we don’t have 120vdc or higher in our homes, I don’t think anyone is interested in using that high of a DC voltage anyway. Also, while DC power will contract your muscles throwing you away from it generally, AC causes them to fibrillate making it difficult or impossible to get away from it.

Therefore, the issue with using 12 or 24vdc is the higher currents involved. Higher current flows create more heat that may need to be dealt with by cooling problem areas somehow. And larger wiring must be used also. As far as squeezing 4000watts from 12 of 24vdc, what’s the problem? All you need to do is put a 500cca automobile battery for example (or possibly two 12v in series if you need 24) in parallel with a power supply/charger; ie an RV 100amp 120vac to 12vdc converter/charger. My DC motors ratings, when combined, are over 5000watts. I never run low on power unless my supply/charger is accidentally unplugged. If that happens I can only get around 5 minutes use out my battery alone before it gets weak. Of course, your results may be different than mine depending on your rigs design and how well balance can be maintained, if at all.

As stated before ...
All you will need for wiring a VFD to control a motor is :
-the pwm signal wire for motor No.1 called PWM1 .
-the two direction signal wires for the same motor [ M1D1 & M1D2 ] .
-the ground .


For converting the PWM1 coming from your controller to a V1 (0-10v analog signal) a separate 2 wires also will come out of it to > the VFD ... you have to make a small circuit as @yobuddy suggested earlier in this post
and the required circuit I'm talking about is the PWM to Analog~EZ ...
As I'll always refer it's originality in this forum to his scoop ... Sorry first post always win



As I added optical coupling and a schmitt trigger inverter 74HC14 for signal shape correction ...

plus some input/output connection modifications to fit the Sim Axe controller ...
I made three of it to my controller as it performs that conversion instantly and effectively ...



This circuit is already tested in my Sim if you need to see it in action (see below link ) ... and for SimAxe compatibility just moved the components to fit in one board ...
Now I suggest that we are going to use a PNP stander in all VFDs ... so we don't have to change transistors and the connection will be without any external power ... except the 12-15v for this board .


these are the doable pdf files that can be DIY used for the SimAxe controller

You tell them Speedy! Its safe if you are using Sim Axe...!

@speedy so to get "my marbles in the right holes" I need this circuit plus Sim Axe or Arduino to interface between my computer and the VFD?

@Martin van Hagen ... Exactly that ... and it is pin to pin compatible with SimAxe controller as is ... Or you have to correctly wire it to the Arduino Or even the old AMC 1.5 or the 1.6 with @prilad FW.

And please note that it is for 2 DOF motors :
- Connect both grounds on each side respectively to there source ... Never combine the ground from the controller with the ground of the 12-15v supply side of the board ... keep them separated as they belong .
- Always use shielded cables for both sides and keep this board and the controller away as much as you can from the VFD's to avoid interference .(audio cables are perfect)
- Be sure that you're using the PNP connection type settings in the VFD .
- V1 / P1d1 / P1d2 are for motor 1 connected to VFD1 ... and so for VFD2 .

yobuddy,
I've heard that "somewhere" before. Sounds like an excellent plan to me.

Many blessings folks,

Tom

So this will be a check in the box for Arduino (Uno V3), which I am more comfortable with and still have a few in my hobby corner.
BTW what is the mode of operation: Speed or Position, as this is a setting within the drives I am thinking of buying?

mainly in this thread we are talking about VFD's ... So, What drives ? Which model ? let us help you here .
the VFD's are generally designed to control motors to give a certain speed in a given time ... So if you used them alone , then you are in speed control mode of operation ...

Adding the Arduino with such interface board to the VFD 0-10v terminals with the proper VFD configurations to continuously receive real-time speed / direction signals ... then you are in position control mode of operation

Are we talking in the same subject here ? Or, why do I feel like you're asking about the Arduino ?