diy seio controller*speed controller

[maxvan1]

I am not too good with circuits, but why can you use a dimmer with a randomly moving motor to turn it?

[A.T.T.R]

im new to ssr so. mosfet what is that?
ill draw p a diagram tommorrow as to where i want the Relays to go as if it were using electromechanical relays and then maybe you guys could help me decide what SSR to use

[vance.110]

Any updates?

[A.T.T.R]

looking for the right relays right now / waiting till next paycheck
still working on my prop tanks and starting a wholesale bussiness

[fatrip]

any new news ATTR???

[stugray]

I would love to hear about ATTR's progress, but I fear that: no new posts means that his concept wont work the way it was originally planned.

I understand exactly how his idea 'should work' he was just unresponsive to suggestions.

I have many ideas for how to make this thing work like this but very little time lately.

Stu

[SuperAWE]

Sounds like Stugray knows a little bit about this subject...

*cough* Occupation: Spacecraft Integration Engineer

[A.T.T.R]

nothing to report havent tried it yet other things take priority besides this
( prop tanks ..... over 3k in those so far)
x mas gifts
food

not easy to do when you work on a lfs pay ( about 8 an hour)

i have come up with some alternative ideas incase this dosnt work. including modified squarewaves ( adds a few extra lines of code and two relays or same number od relays but different type...)
again relays are expensive and i dont have $$ to waste right now

i may take apart my old UPS and see if any parts are in there that i could use

[severum69]

It could be a solution ?
http://www.controlres.com/ac.htm

[Lee_Bay]

Originally posted by severum69
It could be a solution ?
http://www.controlres.com/ac.htm

They also have variable frequency controllers, although I can't find a vendor for them.

[A.T.T.R]

yea i looked at some vfd's but they are all VERY expensive and most seem to require manual control

[stugray]

A.T.T.R

"i may take apart my old UPS and see if any parts are in there that i could use"

NOW you are on the right track. Inside a UPS you will find the equivalent of an inverter that converts 12 VDC into 120 VAC by using a 10X transformer and what is known as a H-bridge circuit.

The circuitry that controls the inverter will have a clock that drives the inverter at 60 Hz. If you can replace that clock with a variable speed clock, your project is done. So dont just look for pieces that you can use, use the enitre UPS.

You were just so set on using 120VDC I didnt want to suggest it.

Also, the VFDs are meant to drive 3 phase motors.

Stu

[Lee_Bay]

Also, the VFDs are meant to drive 3 phase motors.


Specifications

* Input Power: 115 & 230 VAC ±10%
47-64 Hz
Single Phase
* Output Power: 1 kW load rated for three-phase output
800 Watts load rated for single-phase @ 240 VAC
400 Watts load rated for single-phase @ 120 VAC
* Fixed 20 kHz PWM rate
* 0 to 400 Hz output frequency
* Overload current protection
* Controls fan/motor speed based on:
o 4-20 mA control signal
o 2-10 VDC control signal
o Remote temperature sensor (thermistor)
o 0-18 VDC transducer (powered from Stratus)
o Modbus communication link
o Dual control option (i.e. temperature and humidity)
* Storage Temperature: -40°C to 125°C
* Ambient Operating Temperature: -20°C to 40°C

[stugray]

Lee_Bay

That specification means that IF you drive the VFD with single phase INPUT, it has less output capability to drive the three phase output.

Stu

[A.T.T.R]

stugray
i think i was thinking what you were thinking the whole time

the H bridge is what i was making with the relays just skipping the stepup transformer.
i belive my ups IS A SQUARE WAVE OUTPUT

[Lee_Bay]

Stu,

I may be reading the PDF wrong, but I don't think I am. The "Stratus" VFD's "provide precise variable speed control of single and three-phase fans, motors, and pumps".

Also in the "Connections" section, "For single-phase motors, connect motor to positions marked w/t3 and v/t2. For three-phase motors connect to locations w/t3, v/t2, and u/t1."

"Any number of motors may be controlled in parallel from one unit as long as the total current does not exceed the current rating".


The downside is that (and this is speculation) for the price of the thing you could probably buy the Seio (or two). Seems the only vendor is the manufacturer. I haven't contacted them yet to check $$$.

[stugray]

Lee_Bay

I am sure it is possible to drive single phase motors with a VFD, but they are mainly intended for 3 phase so that you can control the direction as well as the speed & torque.

A standard single phase is not guaranteed to start in any one direction unless specifically deisgned ot do so ( like your furnace motor ). If you use one of these drives on a single phase, you cannot guarantee which way it will start up. For pumps like MAGs this doesnt matter, but prop type power heads you do care.

Stu

[SWINGRRRR]

I now ya'll are way outta my league. I spent 8 years doing electronics for the military. (close enough for Government work was a common saying)

What about a stepper motor encase in some kind of plastic. Then just put one of the Dumas Hobby Props on it. Then you could use a simple 555 chip for timing?

Of course the motor would need more modification to loose all the metal, etc.
If I am way off. Tell me to shut up and Ill keep reading.

[WaterbugJenn]

Has any one seen mythbusters Jaime uses a metal box with what looks like a rheostat on the top. He uses it to control the speed of AC motors. That what we need in a smaller package of course. The one he uses is kind of bulky. If I knew what it called I would not be so cryptic. LOL I lost you guys a while back in the thread, but I am very interested in the idea.

[A.T.T.R]

goingto take apart ups now

g/f followed by guitar was distracting me lol

[stugray]

A.T.T.R,

I thought of another way to simplify.

You dont actually need a H-bridge if you use a "center tap 10 to 1 transformer". If you get that transformer, you only need two MOSFETs and 12 Volts.

If you hook the 12V + to the center tap and a MOSFET to each leg, then you drive alternating FETs & the current goes to ground. Each Fet sets up the Mag field in the trasformer in opposite polarities. the other side of the transformer will then OUTput 10X amplitude what you put into the INput side.

If you put essentially a square wave to the input side, you will get an approximation of an AC sine wave out the output side ( due to the inductance of the transformer ).

So I calculated: to drive a SEIO M2600 @ 55Watts ( 120V @ 0.5 Amps ), that will require 12 Volts on the input of the transformer at ~6.25 Amps.

Vary the speed of the square waves driving the FETs, and you have variable speed. Does the processor you are using have 3.3V or 5.0V output logic?

Stu

[A.T.T.R]

it has what ever output i want it to have from 3 to 6 ( outputs about the same as the input used to drive it) most likely going to base what i use to drive this thing on what the relays require to work


currently the program just alternates a single output on and off per powerhead channel ( i was hoping to use a NO and a NC relay so that this would work)
if i have to have two pins alternating on and off that is a simple program change

[A.T.T.R]

help me find the parts and illt ry and throw this together ( once money permits again) i miss when i was a loner and only had to buy gifts for like 2 ppl

[stugray]

I am currently trying to find a transformer. I think that one from an old computer power supply will work in reverse.

If we drive current into the 12V output side of the transformer, you will get ~120V OUT from the input side.

I'll see what I have when I get home. Otherwise I found a company that has some that will step 40V up to 120V but a 40V power supply is more pricey.

Stu

[tbittner]

I just got caught up with this thread and the other one. I'm really curious about how this is all going to work. I've done extensive assembly language programming for the 80x86 processor platform so I was a little lost with the RISC based language. If you need any help, please let me know and I will try my best to help out.