What is the PowerPro inverter for?

[charlese]

Lately I had the message on the PowerPro panel that says "High Inverter Heat"

That got me to thinking (dangerous all by itself).

My meager Knowledge of electronics tells me an Inverter is to increase voltage. I learned that much from inverters in Motor homes. They use battery power (12VDC) to 115VAC in order to run household electrical stuff.

Now my long question - Since the PP runs on 115 or 220VAC What does the inverter increase voltage to? Is part of the PP run on 330V or 440V?

Maybe one of the electronic guys on the forum can tell me if my assessment of an inverter is correct. and make a guess of its purpose.

[BuckeyeDennis]

Lately I had the message on the PowerPro panel that says "High Inverter Heat"

That got me to thinking (dangerous all by itself).

My meager Knowledge of electronics tells me an Inverter is to increase voltage. I learned that much from inverters in Motor homes. They use battery power (12VDC) to 115VAC in order to run household electrical stuff.

Now my long question - Since the PP runs on 115 or 220VAC What does the inverter increase voltage to? Is part of the PP run on 330V or 440V?

Maybe one of the electronic guys on the forum can tell me if my assessment of an inverter is correct. and make a guess of its purpose.

The term "inverter" generally refers to a device that converts a DC voltage into an AC voltage. Most any motor lacking an internal commutator must have an AC voltage applied to make it run -- the AC frequency being generally proportional to the motor RPM.

So an electronic motor drive with an AC line input simply runs it into a DC power supply. (This resulting voltage is referred to as the DC "bus" voltage.) The DC bus feeds the inverter section, which creates an AC waveform of the desired frequency and voltage to run the motor.

[JPG]

The term "inverter" generally refers to a device that converts a DC voltage into an AC voltage. Most any motor lacking an internal commutator must have an AC voltage applied to make it run -- the AC frequency being generally proportional to the motor RPM.

So an electronic motor drive with an AC line input simply runs it into a DC power supply. (This resulting voltage is referred to as the DC "bus" voltage.) The DC bus feeds the inverter section, which creates an AC waveform of the desired frequency and voltage to run the motor.

I doubt I could have said that better!:)

However I think of the PP as a stepping motor, hence it uses a pulse generator rather than a variable frequency AC generator.

[nuhobby]

Yes to all the above....

The PowerPro also advertises "power-factor correction." So the typical troublesome phase-offset between voltage and current, presented at the AC plug, is reduced. The large capacitors in the electronics probably help store energy to apply in the AC/or/pulsed method (to the motor windings) as needed. Those big capacitors I'm guessing may be charged up by an inverter circuit as well, or a switched-mode power supply (SMPS) generally.

An inverter or SMPS probably is doing charge-up work even at 0 rpm, which is why folks hear radio-interference from the PowerPro.

[BuckeyeDennis]

[quote="JPG40504"]I doubt I could have said that better!:)

However I think of the PP as a stepping motor, hence it uses a pulse generator rather than a variable frequency AC generator.]

I'd like to know more about variable-reluctance motors and drives such as in the PowerPro, as I suspect that they might also offer an attractive price/performance ration for some industrial applications. But for now, this article contains just about all that I know about them: http://www.allaboutcircuits.com/vol_2/chpt_13/4.html

So yes, I do believe that the motor itself is essentially a stepper motor. But if I understand correctly, the drive is much more sophisticated -- sort of a brushless motor drive on steriods, working in the pseudo-analog realm, and with enough smarts to compensate for the nonlinear torque vs. current characteristics of the motor. All of which enables it to control motor torque and speed with minimum torque ripple, and with much better energy efficieny than a garden-variety stepper-motor system.

Does anyone know if there is a motor-position feedback sensor on the PP? A clue would be a bundle of four or more small wires connected between the drive and the motor, in addition to the usual (heavy-gauge) motor-winding leads.

[benush26]

Not trying to hijack this thread, but I have the PP and am using 110 but have the ability to add a breaker so that it will be at 220.
Question
Would running it on a 220 circuit make the likelihood of a "high heat" warning, more possible, less possible or no difference?

I do understand that it will increase the HP of the motor, but does it also increase any other problems to watch out for?

Thanks for any info.

Ben

[BuckeyeDennis]

Not trying to hijack this thread, but I have the PP and am using 110 but have the ability to add a breaker so that it will be at 220.
Question
Would running it on a 220 circuit make the likelihood of a "high heat" warning, more possible, less possible or no difference?

I do understand that it will increase the HP of the motor, but does it also increase any other problems to watch out for?

Thanks for any info.

Ben

Take this with a large grain of salt, because I don't know any of the circuit details. But a power-factor-correcting input on a DC power supply contains active switching devices, which enables you to regulate the DC bus voltage. So if it were me, I'd keep the bus voltage the same for either a 110 or 220V input, and optimize the bus capacitors and the inverter output transistors for that voltage. In which case, the inverter would see no difference -- it is isolated from the AC line voltage. But you could still draw more power from the AC line at 220V when you needed to, without the AC line current getting excessive.

[nuhobby]

Does anyone know if there is a motor-position feedback sensor on the PP? A clue would be a bundle of four or more small wires connected between the drive and the motor, in addition to the usual (heavy-gauge) motor-winding leads.

Here was some info provided by charlese back in Jan-2011:


Let me go back and correct my error from two posts ago. The light used is infrared not laser.

The PowerPro manual has - in the troubleshooting section - a statement referring to "Common PowerPro Control Error Messages"

From the Manual:
"The error message is "RPS State Error 0" -
Definition: None of the receivers are sensing infra red light from the receivers.
Possible reasons:
a. Light path is blocked by dust or dirt.
b. Signal cable is broken or has a poor connection.
c. Sensors or electronic components are damaged.

Possible solutions:
a. Remove belt cover and motor pan. Use compressed air to blow dust out from under cowling where where 5-wire connection is made.
b. Check connection of the small, white, 5-pin plug between the Power Supply and Motor. If these wires are cut, they must be repaired or replaced at the factory only. Call Customer Service for shipping instruction.
c. Electronics are repaired or replaced at the Factory only. Call Customer Service for shipping instruction."

[charlese]

Thanks, Guys - Especially Dennis!:) Very interesting!

The light at the end of the tunnel is dim, but at least I can see there is light. A little more study and I might be able to see the actual light source. Oh yea! I'm a little slow, but still "limping" along.

I think I now understand an inverter is used to change AC to DC or vice versa. Not necessarily change voltage. Is that true?

[JPG]

Thanks, Guys - Especially Dennis!:) Very interesting!

The light at the end of the tunnel is dim, but at least I can see there is light. A little more study and I might be able to see the actual light source. Oh yea! I'm a little slow, but still "limping" along.

I think I now understand an inverter is used to change AC to DC or vice versa. Not necessarily change voltage. Is that true?

An 'inverter' changes one type of power source into a different type.

A 'converter' changes one type of power source into another type.

The use of the terms is not always consistent, so that is why the nebulous statements above.