What does VSD-XE NOT control?

[Monacle]

What does VSD-XE NOT control? this would help me to decide or understand to commit to using these controllers all over the place. I am biased towards longer duty 'spindle' operations from surplus motors not wound as steppers, and throwing some encoder on it as needed. Number of wires/ phases gets to be so many variables, nomenclature, same motor being drive 2 different ways = confusion. I need some straight up verification.

1. Start out with a crazy one: Light Bulb or Heater?
ultimate primative 2 wire dimmer task
I guess a temparature to false encoder returns or something.

2. 2 wire motors, 110v USA 12 amp circuit assuming encoder installed? or not needed?:

a. home depot chop saw, sawzall, drill etc. universal motor, chopper or phase angle?

b. induction motor from clothes dryer/washer, Phase angle driven? started by?

c. Treadmill 90volt DC motors, typically brushed I believe. two wire must be chopper driven?

3. Rechargable drill type tools, 'Ryobi' down to 18 volts driving what is typically a mabuchi brushed dc motor.

4. Auto alternator operated backwards as 3 phase motor with rotor field presumably powered up from that 12v source.

4b. is this treated as a 3 phase stepper, but the pole windings are not opposed duplicates or they share slots and over lap so it can be stepper drive?

http://www.cnczone.com/forums/servo_...explained.html

[Monacle]

I would like to continue to edit post one as a wiki,but I see no more edit options.

Brett Schnepf of Blurry Customs reply to an email of this question:
"The Dual DC Brushed the board itself is the same, you use the programming cable to connect it to a computer to "flash" the firmware, for example."

Which does seem to expand the potential further.
If the DC brushed motor control is basically a big dimmer chopper by pulse width modulation, then that mode should control light bulbs and the universal motors found in AC hand tools etc , and the motors found in rechargable type hand tools.

13.1 of the manual has blank notes in DCmotor control, while it does describe Sinosoidal for AC and Trapezoidal for BLDC. 7.2 of the manual shows armature plus and minius for DC modes. The other modes are 3 wire except to a 4 wire Stepper '2ph' mode.

The three phase car alternat0r might work in AC mode, because you could independently engergize the rotor field coil, im not to sure about the 3 phase stepper mode since I have not studied it , but perhaps both modes would work.

The manual says in sec 13, AC as permanant magnet type. The implication is that the 3 phase VFD invertor type control found in a Hitachi or similar VFD is not a a part of the Granite function? So a three phase induction squrriel cage type motor would not work?
If phase non magnetic did work, Less likely a 2phase ac (is supposed to be self starting), and using 2 legs of the granite 3phase might have the wrong angular relation of non 90 degrees.
More unlikely?:Single phase AC motors with an Squirrel cage non magnetic rotor require some method of starting rotation and some method change in voltage frequency to incude a speed of rotation. If the granite device can produce the changeing frequecy from say one leg of the AC mode, or a pulsed DC, and it can cooperate with the motors internal starting scheme, (starting winding, with or without capacitor). The single phase invertor induction motor control is not something I have stumbled upon consciously, I should look around.

What else
Repulsion Motors, have strange brushes
Shaded pole small motors, fans n stuff same as single phase induction? or almost a 4 wire stepper?

[Monacle]

Reply to message 1 sent to Granite Help ticket support [with my comments]:

"VSD-E controls almost any type permanent magnet motor. So it will not drive induction motors or other non-permanent magnet motors. Also motor stepper support is not official yet (but will be become available in futute firware upgrade).

1. Didn't understand
[ this was the light bulb question]

2a) 2 wire motor can be also universal motor, which is not permanent magnet. See: Electric motor - Wikipedia, the free encyclopedia

[universal motor is brushed, but no permanant magnet, the implication from 1 above is that plain chopping speed control may not be on granite as a dumb option, perhaps the sensorless sensing of rotation position is dependent on permanant magnets and the idea of dumbing it down is not built in, perhaps because the idea of a pricey control being used as the swiss army knife single stocking instant motor control is not considered reasonable, If one can stock dumber ones for less, than i suppose that is what I will do.]

2b) no
[induction motors, here I should look for single phase VFD type controllers if they are not considered too dumb when 3 phase are cheaply available]

2c) is this permanent magnet type?
[treadmills generally have been permanant magnet types, not strong magnets as I feel no cogging, so I suppose these will work]

3) Will work, but usually not wort it as drill motors are very bad quality
[mabuchis not good eh? but will work]

4a-b) No experience on starter motors, so I don't know.
[I was talking about alternator type generators. I had not thought of starter motors, but they have such a limited duty cycle, but tons of burst power, so maybe I should look into those]

BTW, any reason not getting a real servo motor?-)"

[speed and certainty of availability, low cost and even free availbility, versatility and inherent features in devices that motors are inside of. It is a lot easier to control a drill with a wired versatile driver than it is to design and control a haptic robot hand. ]

[Al_The_Man]

You wont feel cogging on a DC brushed motor, these can be operated with SCR or PWM type drives.

Starter motors are series wound DC, not suitable for servo or spindle, essentially operate in a run away condition, i.e. should never be run without a load of some kind.
A Universal motor is also a series motor and runs in a runaway condition.
Al.

[vegipete]

I don't know how the Granite Devices VSD actually applies power to a motor, but a typical method for controlling a permanent magnet DC motor involves rapidly reversing voltages with varying symmetry or balance. Think of applying square wave AC power to the DC motor. If the AC is balanced, the motor will just sit there and buzz at the AC frequency. If however the AC waveform is altered so that, for example, it is positive for longer than it is negative, the motor will start to turn in one direction. As the duration of the positive increases relative to the negative, the speed of the motor increases.

Right off it should be obvious that a (filament) light bulb (or a heater) would be unaffected by this and shine at max brightness. (A diode to remove half of the AC waveform might allow brightness control but I wouldn't expect the controller to appreciate such treatment.)

A universal motor (plug in power tool, for example) will also be unaffected by this 'AC' power supply and run at full speed regardless.

The treadmill motor should be a true DC motor that will work fine. The cordless drill motors I've looked at are also normal DC motors that should be controllable.

(Note also that in the real world, motors have inductance which tends to act against rapidly changing waveforms. That's why better servo motors have lower inductances.)

The VSD requires feedback so that it knows what square wave AC to apply to a given motor to get it to turn as commanded.

[Al_The_Man]

Originally Posted by Monacle .The single phase invertor induction motor control is not something I have stumbled upon consciously, I should look around.

Inverter control of 1ph motors is not that successful, they must be Capacitor start AND also capacitor run motors, even then they are susceptible to drop out of run as rpm drops.

Originally Posted by Monacle Shaded pole small motors, fans n stuff same as single phase induction? or almost a 4 wire stepper?

A shaded pole motor is just an alternate way of phase shifting a section of the winding of the motor in order for it to start and run on 1 phase.
It does the job of the capacitor start in a larger 1ph induction motor.
Al.

[Monacle]

55AC AC Variable Voltage Supply | Dart Controls

The heart of the control is a triac fired in a manner to adjust phase and thereby vary speed. The 55 Series is designed to work with shaded pole, permanent split capacitor, permanent split-phase, universal motors or any resistive load. It is not designed for capacitor start motors.
THE 55AC SERIES IS NOT THE EQUIVALENT OF A VARIABLE FREQUENCY / AC INVERTER DRIVE. [this seems to be a giant dimmer]


Bardac Drives: Optidrive E1 AC Drive
Bardac Drives: Optidrive E2 AC Drive

OPTIDRIVE E2 SP SINGLE PHASE MOTOR CONTROLLER
The innovative E2 SP Single Phase motor controller uses a unique control algorithm that ensures reliable starting and control. These drives are designed only for use on Shaded Pole (SP) or Permanent Split Capacitor (PSC) type motors in variable torque, fan and centrigugal pump applications. They use high frequency switching to provide near silent running which is most desireable in applications such as commercial and residential HVAC, fume extraction, laboratories and quiet locations.
[this seems to be an inverter,]


http://www.dartcontrols.com/product-...systems/asp20/
this is a motor encoder plus external digital control interface for all thier drives, not perhaps servo control but better speed control

[Xerxes]

Officially VSD drives are designed for permanent magnet type motors (DC & BLDC & AC). However, 3 phase induction motor may work in stepping motor mode. I haven't tested (as well as non-permanent magnet motors). That's why I won't promise them to work.

In DC motor mode VSD basically acts as current source to inductor. It can be used as current source in many apps. It has been successfully utilized driving high power LED arrays and peltier (temperature control) elements in addition to motors Any DC current controlled device can be driven at least if there's sufficient LC filter after drive.

[Monacle]

Xerxes has presented interesting and wide parameters for experimentation of VSD versatility.
2 issues still undefined for the architecture of ultimate flexibility applications experimentation are:

1. Why does an SCR or Triac control not use a isolation transformer, 1 to 1 for example? where VSD and some other controller 'servo' manuals (Dugong) demand isolation transformers. Are the described high grounding currents not found in SCR's simple chopping? They do have braking resistors. Can the VSD logic inputs be optoisolated? Do VFD controllers from Hitachi et al have a transformer inside before the IGBT's? What is the least heavy and bulky method of achieving isolation? and the estimated wieght? Enclosure of double insulation methods is beneficial?

2. If a second absolute encoder is placed downstream from the motor shaft, at the furthest end of all the belts/gears/ballscrews/dovetails, I presume and read that the ability to correct for slip or backlash depends upon commands sent externally to the VSD from some external program or device, and that many programs are speaking in the language of stepper motors that is reinterpreted by the VSD or other device. The architectures of external boards or software, such as Mach 3 to achieve 2nd absolute encoding at the far end and command corrections or aborts or shut downs to the VSD is something I have not yet mastered. Any advice?

[Al_The_Man]

1/ In the case of SCR controllers such as KB and Baldor that are fed across the 120/240 volt AC supply there is no need for isolation as in the simple application the control is operated by a suitable metal frame pot and relay contact.
If a separate external analogue control is required, the above brands can supply an isolation add-on.
I am not sure what ground currents you are referring to as there should be none even in a properly grounded motor.
There are also many manuf. of drives that allow the optional practice of re-referencing to earth ground the -ve side of isolated DC supply to their PWM drives, I have done this on many applications.
In the case of VFD's, the common practice is to place a 3 phase bridge across the incoming supply, hence the DC for the motor supply is not isolated from ground.
For their low logic DC supply, a isolated switching or other type of electronically generated supply is provided for the I/O and analogue control which can be referenced to earth ground if required.
I have come across at least one that had a 1ph isolation transformer across two of the input terminals, but this is not the norm.

2/ In the case of double loop feedback as in the case of motor encoder, and say a linear scale on the final actuator, if anything other than a small degree of backlash exists in the mechanism, it can cause hunting.
This requires special tuning in the PID loop, there is an excellent video tutorial on the Galil Motion site that covers this, and applies to other products other than Galil.
Al.