Did I Kill My Cyclone Motor?

[Tom Slick]

Is the DC 120v or 220v? either way you will have to separate the 3 wires in the cord and take a reading from just one wire. if it is a clamp meter you will clamp around only one wire.

we used to take a plug and a receptacle and run 3 individual wires between the 2. think of a really short extension cord with 3 individual wires instead of the wires wrapped in the cord.

[LCHIEN]

Is the DC 120v or 220v? either way you will have to separate the 3 wires in the cord and take a reading from just one wire. if it is a clamp meter you will clamp around only one wire.

we used to take a plug and a receptacle and run 3 individual wires between the 2. think of a really short extension cord with 3 individual wires instead of the wires wrapped in the cord.

If you are careful, you can slit about four inches of the outer jacket of an extension cord and cut around the jacket and remove the four inches of jacket, exposing (but don't cut the inner wires insulation) the internal wires. The black and white usually are the hot and neutral, you can measure the black wire (and the white should have the same current, too) with the clamp around meter. Don't cut the fiber cords (part of the cable strain relief).

If you don't cut the inner wire's insulation then it should be perfectly safe as long as you don't pull on the cord real hard (part of the strain reliefing is now gone).

[TheRic]

When I first read this thread I thought since Thom was helping you, did it suck up Thom's thong??!! Then I thought no I don't want to know how it it sucked up this thong!!!

Sorry to hear about the problem. Glad to hear you figured it out what the problem was.

[LCHIEN]

reviewing this thread, I saw several suggestions that you check the switch for damage...

I doubt its damaged. The normal starting surge for a big induction motor like that is probably much higher than the sustained current that killed your motor. The switch gets the most abuse on starting when it conducts the surge current and when it is opened under load and breaks the current causing arcing.

Having an overcurrent situation and the motor quit and pop the breaker would probably not have damaged the switch.

The sustained current that damaged your motor probably was like 120% or even 110% of rated current compared to 600% surge current on startup that does not last.

When the motor is run past the rated current then the magnetic fields in the armature were higher than the iron could handle, the field saturated and the extra current went into heat rather than magnetic field. Probably the extra heat reduced the magnetic field capability even more, generating even more heat. This in turn melted the winding insulation and caused parts to short out.

it might have taken quite a few minutes to build up the initial heat but eventually it probably went pretty fast.

[Jeffrey Schronce]

reviewing this thread, I saw several suggestions that you check the switch for damage...

I doubt its damaged. The normal starting surge for a big induction motor like that is probably much higher than the sustained current that killed your motor. The switch gets the most abuse on starting when it conducts the surge current and when it is opened under load and breaks the current causing arcing.

Having an overcurrent situation and the motor quit and pop the breaker would probably not have damaged the switch.

The sustained current that damaged your motor probably was like 120% or even 110% of rated current compared to 600% surge current on startup that does not last.

When the motor is run past the rated current then the magnetic fields in the armature were higher than the iron could handle, the field saturated and the extra current went into heat rather than magnetic field. Probably the extra heat reduced the magnetic field capability even more, generating even more heat. This in turn melted the winding insulation and caused parts to short out.

it might have taken quite a few minutes to build up the initial heat but eventually it probably went pretty fast.

Thanks Loring. That is actually a really good explaination of what happened that I can understand. I really appreciate your help on this matter!

Ric, wasn't worried about the thong but first thought was "man I saw some extra cats around here today" and then I remembered the Cat Sucker 2000 in another thread!

[Jeffrey Schronce]

I called Wilke today to discuss the issue. They advised it was under warrenty and would replace the motor. I told them that I burned the motor up and all I was looking to them for was advice/parts. They said if I brought the top half of the cyclone in they would replace motor, test switch, check bearings, balance blower, etc. They would charge the cost of the motor. Pretty good service IMHO.

[cgallery]

I called Wilke today to discuss the issue. They advised it was under warrenty and would replace the motor. I told them that I burned the motor up and all I was looking to them for was advice/parts. They said if I brought the top half of the cyclone in they would replace motor, test switch, check bearings, balance blower, etc. They would charge the cost of the motor. Pretty good service IMHO.

Well, kudos to you too for being honest with them. I'll bet that was the exception for them, not the rule.

[Jeffrey Schronce]

Question for you physics jockeys out there . . . .

When I get the cyclone fixed and properly put back together will I notice more suction at the gates? Was I loosing suction at the intake due to the lid being off the unit? Logic tells me, yes it was loosing a lot of suction at the opening but then again I don't fully understand the physics of cyclonic action.

[cgallery]

Question for you physics jockeys out there . . . .

When I get the cyclone fixed and properly put back together will I notice more suction at the gates? Was I loosing suction at the intake due to the lid being off the unit? Logic tells me, yes it was loosing a lot of suction at the opening but then again I don't fully understand the physics of cyclonic action.

I would suspect that you would get improved airflow at the blast gates. But I thought I had a good handle on cyclones until I read that...

You can place a cyclone outside your building with no drop box. You need to use it in a push configuration (so the blower is pushing air w/ suspended particles into the cyclone's inlet), The outlet is piped back into the shop. The cone empties on the ground. A large percentage of the shop air will actually make it back to the shop via the outlet. I would have thought that it would all blast out the bottom of the cyclone, but apparently is doesn't.

[LCHIEN]

Question for you physics jockeys out there . . . .

When I get the cyclone fixed and properly put back together will I notice more suction at the gates? Was I loosing suction at the intake due to the lid being off the unit? Logic tells me, yes it was loosing a lot of suction at the opening but then again I don't fully understand the physics of cyclonic action.

I don't 100% understand your question here, maybe there's confusion on terms.
Most people confuse airflow and static pressure. And what is suction? Is that more pressure or flow? What is it in your question... Science is very precise. In the context of your question I think you imply suction is the ability to pull stuff in. Kind of a qualitative thing rather than something you can measure like airflow or pressure.

Also, more suction comared to what? And I don't really have a mental picture of your specific system.

But here's general characteristics of how a DC blower works:

The impellor turns at a constant rate, the air volume in the blades is a fixed amount. ideally it would flow that volume per turn if there was no resistance to flow. When there's resistance the blades can't force all the air forward, it leaks around the impellor which is not sealed, and airflow goes down and pressure increases.

If you have little or no restriction the air flow readily, no pressure requred and maximum air flow. With a short hose and an open cyclone lid, the flow of course comes in the lid rather than down the line at the gate. When the air is flowing freely, the motor current will be at its maximum, becaue moving air is work.

Close the lid, run a lot of hose to the tool and gate, then the pressure increases and the flow reduces.

The pressure does not move anything, its the airflow that carries dust and paricles. Close off the gate and hose the DC will roar and be generating maximum vacuum pressure in the hose, but there's no flow. The roar comes from the air protesting as the impellor tries to push it but it won't go. Actually the motor current at this point will be at its lowest operating point, because its not really moving much air.

I hope that enables you to answer your question.

[Jeffrey Schronce]

Yes, that answers my question.

I was wondering if CFM at the machine was higher or lower with the dust bin lid off. Sounds as if it would have been higher as max airflow would occur with the lesser pressure (of course at the expense of the motors amperage!).

Thanks
Jeff

[reddog552]

Amp meter

It sounds to me to be a bad Motor although I dont think it was your fault. the motor should have cooled itself,under most situations including top off,I agree there should have been thermal protection. Here is a cheaper multimeter with amp probe, sorry there not cheap. http://www.lowes.com/lowes/lkn?actio...600&lpage=none

[cgallery]

Most people confuse airflow and static pressure. And what is suction? Is that more pressure or flow?

What I've observed when people test a dust port is that they tend to place their hand several inches from the port. Then they gradually move their hand closer and closer to the port.

The first step allows them to determine (roughly) the amount of air flowing. The second step allows them to determine (again, roughly) pressure.

I don't know if this is the brain protecting us from unknown dangers or if people actually subconsciously understand the difference between CFM and static pressure.

However, I think I've also noticed that when people ask in these types of forums whether they will get more "suck," they want to know if either will increase. Of course, for woodworking, either is welcome. More CFM is great for big machines. More pressure is great for machines with small ports.

[gsmittle]

I had this problem on my first table saw motor - but it was thermally protected so I only had a panic the first time it happened. Having written this, I now realize that I have just condemned the BT-3x00 design because it lacks thermal protection on the motor...

Isn't that what the belts are for?

g.

[LCHIEN]

Isn't that what the belts are for?

g.

The belts will protect it from a total stall of the motor
but won't keep it from self destruction when the motor is loaded to 120% of capacity and kept running that way for a long period of time.