Skeletons in my Closet!

[supremewhirlpol]

the LOGO! mounting is DIN rail, requires 12/24VDC power. I mount it on the end next to the option switches on the console.

 

[supremewhirlpol]

The LOGO! needs a power supply, the machine start relay needed to be moved.

 

[supremewhirlpol]

VFD control is LVDC. The LOGO! interfaces the signals of the machine to something that is understandable to the VFD. On the VFD, I use terminals 8-14.

 

[supremewhirlpol]

terminals 8, 10 are connected together. Terminal 9 is the 12V+ DC signal, is gets used with the rest of the terminals.

 

[supremewhirlpol]

At this point, configuration of the VFD is finished!

 

[supremewhirlpol]

Now its time to wire the LOGO!

At the bottom of the LOGO!:
Start (FEW) signal is wired to Q1 with +12VDC signal
Start (REV) signal is wired to Q2 with +12VDC signal
Constant speed 1 is wired to Q3 with +12VDC signal
Constant speed 2 is wired to Q4 with +12VDC signal

At the top of the LOGO!:
I1 is +24VDC signal from the tumble relay
I2 is +24VDC signal from the spin relay

Logic(from LOGO! to VFD):

For tumble:
Q1=high
Q2=low
Q3=high
Q4=low

To stop: Q1=low

For spin:
Q1=high
Q2=low
Q3=low
Q4=high

To stop: Q1=low

 

[supremewhirlpol]

Now! I need logic from the machine to tell the LOGO! what to do. For that I use 2 more relays with 110V coils. These relays act on the contactors that power the VFD and drain pump. The coils are powered by the actions of the contactors, but these two relays switch LVDC going to the inputs of the LOGO!.

 

[supremewhirlpol]

I could have used the extra terminals in the contactors to do this, but I make it a point to isolate the DC signals from the AC signals!

 

[supremewhirlpol]

They are labeled accordingly.

Logic(input to LOGO!):
Tumble relay = high = I1: high
Spin relay = high = I2: high

tumble sequence:
I1 = high
I2 = low

spin sequence:
I1 = high
I2 = high

nothing:
I1 = low
I2 = low

I1 = low
I2 = high

 

[qualin]

Are you still going to use the original timer which came with the machine? I'm confused because you are using a PLC, but wouldn't the timer be enough to send the right signals to the VFD? Couldn't the PLC just be replaced with relay logic?

Stupid question, I know.. but this is downright fascinating.

 

[tolivac]

I like how this project unfolds-peice at a time-won't ask questions until Melvin completes it.

 

[1966_mustang]

Man you have done ALOT of work on this...How are you going to couple the pump up?

Also I see you use alot of 3 pahes AC motors with variable frequency drives....could you have also used a DC motor? I mean bridge the AC with some heavy diodes then put it through some caps, and then run a PWM DC motor speed control would this work as well?

Very interesting project! Keep up the good work

 

[supremewhirlpol]

Qualin:
Yes, Use the original timer for the other operations of the machine. Yes, I could have used just relay logic with timed relays and the such for signaling the VFD, however I want to be able to change the tumble and spin sequences. Using just the relay logic won't allow me to do that as easily, also remember that I have removed the speed changing gear motor. The current modification does not include the leg switch for detecting out of balance conditions. The PLC will allow me to incorporate that feature with just some wiring and a programming change. If you have anymore questions, just post them. We will step through them!

1966_mustang:
For the pump, it has its own contactor, if you look above to post# 562708. The original motor was reversible. I use the wire to make the motor reverse during spin and condense to fire the contactor for the pump. As I now remember, I'll have to rewire it as I am also using these same lines to supply the pump, when I really just want to use the wire fire the contactor,and the supply to the pump should come direct from the terminal block of the machine.

You bring up a good point about using a DC motor. Building my own controller for it is quite involved. There are several ways to do it. Interestingly, a friend and I are currently working on building a controller for a zero-torque 3 phase BLDC motor. For the phase switching, one could use an H-bridge, as it already has the transistors and the diodes to protect them. You can also use a circuit of 3 MOSFETS, or a circuit of 6 MOSFETS, use a massive Bridge rectifier and capacitor bank so that the supply stays constant under load. Then use a micro controller like a PIC 18 or arduino to fire the MOSFETS. The problem of the BLDC motor is that you have to know when to fire the MOSFETS. This is dependent on the rotation position of the motor. The rotation position is always subject to change due to load. If the firing of the MOSFETS or IGBTs is not on cue with the rotation position, you get a break-down in speed and a stalled motor. To correct this problem, you can use a hall-effect sensor, or go the vector-less approach. The vector-less approach is is somewhat complicated, as you have to detect the zero-crossing moment as the shaft of the motor rotates. This involves building a low-pass filter that is good enough to discard the other noise, due to the switching frequency of the MOSFETS, spikes, and other transients that ride in the system. Then you must detect the zero-crossing moment in the bief moment that the MOSFETS, IGBTs are switched off and the motor becomes a generator. Take that signal, convert it to a digital signal that the micro-controller can deal with, then fire the MOSFETS, IGBTs appropritely. Use a capacitor switching circuit to start the motor.

It is very possible to do this, but complicated. For that, baby steps first. I do small-scale implementation first, then tackle a project building a controller for say a 1hp TEFC BLDC motor.

 

[qualin]

Melvin,

What on Earth do you do for a living that you know all of this stuff?

 

[chestermikeuk]

Motor Controller

Wow, admiring your ingenuity and perseverance with the GE project Melvin, you make it look so easy, looking forward to seeing the lessons completed.....maths and electrical conversion stats are not my thing but cant wait for the water testing...

Cheers, Mike

 

[1966_mustang]

I know I fool around with motor controllers my self. Three pase ac motor controllers are expensive and complicated to build. My background is EV world. There are pluses to both AC and DC motor systems.. Treadmills I know uses DC motors. AC over does not buy you that much effececy as DC. Now on a smaller scale like the RC hobby stuff. BLDC motors are more effiecent than PM DC motors. But as power of the application goes up, Field wound DC motors become as attractive as AC motors.

I personally like using DC controllers when at all possible, uses only one Silicon device and free wheeling diode, instead of 6 silicon devices like AC.

good luck keep us posted...even if I never find my 60's whirlpool machine (which is what it looking like), I like looking at what your doing..

 

[supremewhirlpol]

166_mustang:
I think you will find your machine eventually. You may have to look harder, It will turn up. Then it is just a matter of distance and what you are willing to do in order to get it to you. For Field wound DC motors, are you talking about Field circuit + brush circuit?

ChesterMikeuk:
So far it has been easy, you just think it out. The hard part as I'm finding out is using the software for the LOGO! I was trained on Allen Bradley SLC 500 and compact logix 5000. The software for the LOGO! is a bit different, and it has its own unique set of quirks that I have to get used to.

Qualin:
been playing with motors, electricity since ~5 years old. Working on my college degrees now.

 

[supremewhirlpol]

Success!!!

It walks, talks, kicks, poops, and pees! Need to make a minor change in the program. Need to change some settings in the VFD to properly reflect the load. Have another idea i'm going to implement.

 

[toploader55]

Congratulations !!!

Can't wait to see it running. Eddie