Hi, I’m Hus. I’m the CEO of Infinispark. I have more than 12 years of experience in the electrotechnology training industry, so I understand the concerns of compliance, learner attrition, and the increasing demands on trainer’s time.

Welcome to Motor Faults Pracbox video. In this video, I will show you how the Motor Faults Pracbox can cover multiple core units of competency, how one pracbox can replace 65 motors, how it will allow flexibility in training and save time in classroom scheduling. Towards the end of the video, I will transform a working motor in the Motor Faults Pracbox to a faulty one and then back, so please stay tuned for that. The Motor Faults Pracbox is designed for AC machines and fault-finding units of Certificate III in Electrotechnology. The working motors cover the induction motor part of AC machines. And since you can introduce faults in these motors, you can then use them for fault-finding and troubleshooting unit. There is an obvious cost saving there.

Let me go through the components in the Motor Faults Pracbox so I can show you how one Motor Faults Pracbox can replace 65 motors. On this side of the Motor Faults Pracbox, we have a three-phase induction motor that’s extra low voltage. So, it needs either 41.5 or 24 volts. As you can see, the terminals here are laid out as if it’s on a real motor, where the winding U, for example, is going from U1 to U2 on across on an angle. The earth terminal is connected to the frame, so you’ll be able to do the tests from the frame to this earth terminal. On this side, we have a single-phase induction motor, which is designed in a way that you can connect four different types of motors with it. So you can connect it as a split phase, you can connect it as a capacitor start, capacity run, and capacity start and run. So, we have multiple components here to enable you to do that.

We have this resistor. If you put that resistor in series with auxiliary winding, you will be able to create that phase shift that you need for single-phase motors. If you were to use this toggle switch, that toggle switch is there to show the operation of a centrifugal switch or a start relay. What’s better about this toggle switch, as compared to a centrifugal or a start relay, is that you can control this as you want. Those things, you might not be able to control. For example, the centrifugal relay is relying on the centrifugal force off the motor. So, you can’t control that. But this switch, you can.

Then we’ve got two capacitors here. One capacitor, this blue 122 microfarad, that’s a start capacitor. And this capacitor, black one, that’s a 7 microfarad run capacitor. Again, with different combinations, you will be able to connect this motor in as different types of motors. Coming in the middle, we have a touchscreen that allows you to induce faults into these motors. So as you can see, there are two buttons here. If I go to three-phase faults, now I have a screen that shows an option of 30 faults. Now, these are 30 sets of faults. From fault 1 to fault 10, there is a single fault in this motor. So if I go fault 7, for example, now there is one fault here. Fault 11 to 20, there is dual faults. And fault 21 to 30, there are three faults. So, this allows the students to have more practice in testing, but at the same time, gives them that sense of progression or achievement. If I return, all faults turn off. And if I go to single phase, I see a similar screen, but the faults will now be on this side.

So if you look at this, there are 30 faults on the single phase that you can turn on, and 30 sets of faults on the three-phase. Now, for the usage, we suggest that if you’re using this Motor Faults Pracbox for fault-finding and if you’ve got the fault system on, only do the fault-finding. Don’t power these motors up. And the reason for that is once you have a fault enabled, you’re not sure what that fault is. It could be a short circuit fault, which might damage the equipment. So if you want to power these motors up, best thing to do is disconnect it and turn off the fault system. So now, since the fault system is off, there are no faults here. You will be able to power these motors up for AC machines.

The single-phase induction motor used here can be wired as four different motors. So including the three-phase motor, there are five working motors. Now, introducing faults into any motor is usually a permanent process. So if you wanted a faulty motor, you would have to damage them. The Motor Faults Pracbox allows 30 sets of faults that can be introduced in each of these motors temporarily. To replicate that, you will need another 60 damaged motors. That’s the total of 65 motors, including the working ones. So, one Motor Faults Pracbox can potentially replace 65 motors. It can save you thousands of dollars, and solve the storage and logistical problems that could arise from having so many motors. And imagine the possibilities of practical training it can offer.

Traditionally, the training organizations have had to dedicate a room to motor training because of the lack of portability. This can be a nightmare for classroom scheduling where there are multiple groups doing the same units. Motor Faults Pracbox is extremely portable. For induction motor training, you need a three-phase extra low voltage supply. And for fault-finding training, you just need a supply from a standard socket outlet. When combined with our product called Portaphase, the Motor Faults Pracbox offers amazing flexibility. You will be able to turn any classroom into a workshop with a moment’s notice, and at no extra cost. To prove my point, let me show you the Motor Faults Pracbox in action.

Let’s connect this three-phase motor in star and then delta, and then compare the current that this motor draws, so we can see the difference between them. So to connect it in star, I will go from red phase to red phase, white to white, and blue phase to blue phase. Now, since this is a balanced load, I don’t really need the neutral to go back, so all I need is a star point. So, I will create a star point. So now, I have a star point. I have the lines going into the motor. All I need is power coming from the distro box. So let’s turn this on, and turn that on. So as we turn that on, you can see that this motor is spinning. Now, the beauty about this pracbox is you can actually feel the torque by just trying to stop the motor by hand without hurting yourself. The way they’re designed is the torque is not high enough to cause any damage.

This wouldn’t be possible in real world. They will never be able to touch the shaft of a motor, a real motor. But in this case, since we are using lesser voltage, we are able to control that, and then see how that goes. So, let’s try and measure the current for this so we can compare it with the delta connection. So to measure the current, we will connect one of our lines to the ammeter. We’ll set it to AC, and let’s turn that on. So turning it on, I’ve got the motor running. I’ve got the current of 146 milliamps. If I stall this motor, so hold it and stop it, then the current goes up to about 390 milliamps. So, you can tell that if you’re stalling a motor, there will be a higher current drone.

Now, let’s convert the connection of this motor from star to delta. The lines stay connected, but instead of the star point, we will now link the connections of the delta. So U1 goes to W2, V1 goes to U2, and W1 goes to V2. Now, we’ve connected the same motor in delta formation. So, let’s turn that on. Still turning, but we don’t really know how different it is until we try and stop it, and it’s a lot harder to stop. As you can tell, I’m struggling. Let’s try and measure the current to see the difference. So, we’ll change that. So line 1 is now going through the ammeter. Let’s turn it on. So under no load, we’ve got a current of 470 milliamps as compared to 147 milliamps. But if I try to stall it, I’m getting about 1.1 amp instead of 390 milliamps in the star connection. So there, you can see the difference between star and delta connection is that you’re getting a lot higher torque, but it is drawing a lot more current compared to the star connection.

Now, we’ll connect this single-phase motor in split-phase formation, and then the same motor will change it to cap start. So, let’s start by connecting our supply. And we’ll start by connecting the supply across the main winding. So right now, we’ve got the main winding connected, but nothing else. So, let’s see what happens if I turn the power on. So with the power turned on, you can see that it’s not turning, but if I was to give it a little kick, we can see that the motor starts spinning. So, all it really needs is that little kick. You need a starting circuit for the single-phase induction motor. Let’s give it that starting circuit. So from one side of the auxiliary winding, we’ll go to the… Sorry, one side of the main winding, we’ll go to the auxiliary winding, and other side of the main winding will also go to the auxiliary winding. These two windings are physically apart from each other inside the motor, but turning it on will not do anything. As you can see, it doesn’t do anything. The reason for that is because it doesn’t have electrical phase shift.

So to cause electrical phase shift, we will have to include some other parts in the circuit. So, we’re going to introduce this resistor and the switch, which will act as a centrifugal switch. So, let’s connect that. So from the auxiliary winding, we’ll connect the resistor. The resistor will go to our switch, which is going to act like a centrifugal switch. And from the switch, we will return to the main winding. Now, if I turn the centrifugal switch on, which is what happens in normal situation, that when the motor is turned off, the centrifugal switch is engaged. So, let’s turn that on now. As you can see, the shaft is spinning. So earlier, it wasn’t. But now, just by adding that resistance, what we’ve done is we’ve created an electrical phase shift, and that shaft is spinning now. Once that shaft reaches a certain point in a motor, the centrifugal switch will open. And if we open that, you can see that it continues turning.

Now, split-phase motor doesn’t have a lot of torque. So if I try and stop the motor, I can. And in that case, the centrifugal switch would come on and it will start moving again. Even in this case, I can actually stop it. The reason, because split-phase induction motors don’t have a lot of torque. To increase that torque, we’re going to introduce a start capacitor. So, let’s do that. So instead of going to the centrifugal switch, we’re going to go from the resistor to the start capacitor. From the start capacitor to the centrifugal switch, or the toggle switch, and from the toggle switch back to the mode, to the main winding. So, let’s turn that on now and see what happens. Now we’ve got the shaft running, and it’s a little bit harder to stop it. Now, once it’s spinning, and if the centrifugal switch cuts off, the motor continues to spin. And if I try and stop that, the centrifugal switch would come back on and the motor would continue to spin. So, a cap start motor would have a lot more torque compared to a split-phase motor.

Now, in the same way we can connect it to a permanent split cap motor, and cap start and cap run motors as well. Now, I’m going to transform this three-phase motor from a working motor to a faulty motor, and then bring it back. To confirm that this is working, let’s do a couple of tests. So to do those tests, I will set this ohmmeter to 500 ohms, and I’m going to confirm that the meter reading is accurate. So right now, it’s showing 0 ohms when I showed these two. So, let’s start with measuring resistance of winding U. I can see that it’s 8 ohms. Resistance of winding V is showing 8 ohms, and resistance of winding W is also showing 8 ohms. Now, there are a few more tests to go, but let’s just go with these three, and see what we can do to affect the resistances and the values. So, we’ll go to three-phase faults and we’ll set fault number one. Let’s repeat those three tests and see what we get this time.

Winding U, we get 8 ohms, as expected. Winding V, we’re getting the resistance is outside the range. It’s definitely more than 500 ohms, so that’s obviously not correct. Because in the previous one, when the motor was working, we knew there was supposed to be 8 ohms. Let’s repeat that test for W and see if it’s good, and that’s still showing 8 ohms. So just by adding that fault one, what we’ve done is we’ve created a fault on winding V. Let’s remove that fault and repeat that measurement. So winding U, still 8. Winding V is now 8 again, right? So, what we did was we transformed this motor into faulty one and then brought it back.

Let’s do that again with another fault, so fault number five. Let’s repeat that test, winding U, 8 ohms, as expected. Winding V, also 8 ohms. And winding W is showing almost short circuit. So that winding is now short-circuited, so it’s another fault. Again, as I said, there are a few more tests to do to confirm that the motor is faulty or working. But just from these three tests, we could tell that we turned this motor from good motor, working motor, to a faulty motor, back. And now, we’re going to remove the faults again. And as soon as we do, you can see winding W goes back to 8 ohms.

Jo O’Mahoney:
I thought it instilled that what I’d been teaching on the board was actually right. So, they’re doing it for a reason. So I’ve given the theory side of things, and they’re sitting down and actually measuring, and doing, and seeing that the results are what I told them. So, they believe in me.

Hus:
We offer ongoing phone and email support so you will always feel supported. Our aim at Infinispark is to work with you to maintain compliance, increase learner engagement, and give the trainers back some time. Please get in touch with us to see how we can work together. Thanks for watching.