Friendly Consumer alert

Beau Schwabe · 2014-01-21 20:35

So I went to the local hardware store to pick up a speed controller for a ceiling fan.... I wanted the older style with the knob rather than a slider.

For some dumb reason when you turn it "ON" the fan starts out at full speed, and then tapers off as you turn it further to the right. I wanted the opposite mode of operation so I opened the plastic cover. ( Simply take a drill and bore out the brass rivets and the cover comes right off )

I was appalled at the poor point to point solder construction ... I guess I at least expected a circuit board! ... They even used masking tape as an insulator !! I won't give any brand names, but this speed controller is supposedly made in the USA ... Pennsylvania to be specific. (See attached images)

I was able to reverse the operation by swapping the outer leg of the potentiometer, and where the rivets were, I replaced them with 6-32 machine screws.

Now that I know what is "under the hood", I'm still a little uneasy.

Anyway take this however you want with your own grain of salt.

User Name · 2014-01-21 20:57

Is the coil wound around a glass fuse? If so, it's an odd thing to see in a commercial product.

Phil Pilgrim (PhiPi) · 2014-01-21 20:59

Beau,

There might be a good reason they did it that way. Two-speed fans are also switched Off->High->Low. I think it's to make sure the motor actually starts before you slow it down. Otherwise it might stall when you first turn it on without giving it the extra kick.

-Phil

Heater. · 2014-01-21 21:00

Good grief. That looks like something I might have made. When I was 12 !

Phil Pilgrim (PhiPi) · 2014-01-21 21:03

heater wrote:

Good grief. That looks like something I might have made. When I was 12 !

Who's to say that those who assembled it were any older?

-Phil

Beau Schwabe · 2014-01-21 21:47

User Name,

The "Coil" is a small choke around a ferrite rod.

Phil,

"There might be a good reason they did it that way. Two-speed fans are also switched Off->High->Low" ... perhaps, but this application will be driving a sewing machine motor and it starts up just fine.

LoopyByteloose · 2014-01-21 22:14

Phil is right again. All a/c fan motor controllers are generally set up to start in High speed mode as the motor has to overcome the inertial of not moving. In the case of fan motors, many build up grime in their bearings over time and won't even start at high speed unless you clean up the bearings. I just replaced one that I had cleaned about 5 or 6 times over 10 years as it just would no longer start.. even with the clean up.

As far as the workmanship....
It is the use of masking tape for insulation that really has got me wondering. Soldering and then enclosing in a non-conductive, fire retardant box might allow a lot of leeway for other sins, but masking tape is neither reasonalbe insulation nor durable.

RS_Jim · 2014-01-22 13:32

Good grief, did this device have a UL label ?
Jim

erco · 2014-01-22 13:52

Phil Pilgrim (PhiPi) wrote: »

There might be a good reason they did it that way. Two-speed fans are also switched Off->High->Low. I think it's to make sure the motor actually starts before you slow it down. Otherwise it might stall when you first turn it on without giving it the extra kick.

+1, that's how every 3-speed ceiling fan & box fan I've ever seen is wired. I've come to the same conclusion as PhiPi, that it's a safety thing.

Duane C. Johnson · 2014-01-22 14:03

I am not about to excuse such shoddy workmanship.

However, I suspect the tape is not actually "Masking Tape" which is usually paper based.
It looks to me like a plastic fiber based tape usually used as insulation. Often used by motor winding guys.

As for the U/L is concerned.
They have a hard job to do.
Sometimes they have to just "hold their noses" when stuff like this actually passes the Hy-Pot and other tests.

Hey, it passed, what else can you say.

Duane J

Beau Schwabe · 2014-01-22 16:07

RS_Jim
"Good grief, did this device have a UL label ?" - Yes Sir! stamped right on the metal on the front face.

Duane,
"However, I suspect the tape is not actually "Masking Tape"" - It looks, and feels like athletic cloth tape

Rforbes · 2014-01-22 17:10

The tape is commonly called heat tape. It resists deterioration caused by heat and is usually made of a very thin fibreglass. It almost always tears and/or cracks when messed with. It's use in ovens at the connection of the element to conductor is very common because it is cheaper than an insulated terminal. It actually pretty good stuff- just delicate.

kwinn · 2014-01-22 19:15

You might be surprised at how much equipment is built with parts that are assembled in that manner, some of them with price tags in the tens of thousands or even over the $100,000.00 dollar mark. Phototube assemblies are the most common one that comes to mind. On the other hand the layout and soldering is much better, and the assembly is usually potted.

Duane C. Johnson · 2014-01-22 19:22

Hi Rforbes;

Rforbes wrote: »

The tape is commonly called heat tape. It resists deterioration caused by heat and is usually made of a very thin fibreglass. It almost always tears and/or cracks when messed with. It's use in ovens at the connection of the element to conductor is very common because it is cheaper than an insulated terminal. It actually pretty good stuff- just delicate.

Ya, that's the stuff. You often see it with the glue side stuck to glue side as in the top of the second image. The glue on this tape hardens after a while so it gets kind of welded to itself. Fairly permanent. Better than conventionally wrapping around where the glue sticks to the back of the last wrap. Looks a bit crude but effective.

Personally, I like the brown colored "Kapton" tape but this is a lot more expensive.

Duane J

Friendly Consumer alert

Comments