Need help determining Ohm value of resistor.

[CAS]

Glad to see you got your fan all up and working. Now you just have to work out what the next project is!

[ToddB66]

Thread Titled: Need help determining Ohm value of resistor.

Hi CAS !

First, I received your "Grab Bag" of electronic components today, April 14, 2015 !

With all the different colors, it reminded me of a bag of jewels !

I'll have some fun now and learn more while identifying these components for future use.


Second, thanks to your help, I've completed my fume fan for soldering and a couple of pictures are attached below.

As you instructed, I connected the two black wires from the Speed Control in series with one of the white wires from the motor and the Fan works great ! Then I hot glued the Lutron Speed Control to the back of the 'True Air' fan and then hot glued a thick block of Masonite to the underside of the Speed Control to serve as a steady-rest foot.

I can't thank you enough for all of your kind help.

Your friend,

ToddB66

[ToddB66]

Thread Titled: Need help determining Ohm value of resistor.

Dear CAS,

Well, in one of my earlier posts I had decided to put the Hamilton Beach "True Air" wall fan back together and use "as is" without a speed control device, but after thinking about it and getting more answers from you I decided to go ahead with my original plan and splice the LUTRON Speed Control device into the fan circuit and I did that today. As I promised to report, the results were as follows:

Everything works, except the speed control dial operates in reverse. Starting with the dial turned all the way counter-clockwise to the OFF position , when I turn the Speed Control dial clockwise to the ON position the RPM's of the motor are at it's highest speed and then begin to slow down as I continue to turn the dial clockwise.

I would prefer that when the dial is first clicked ON in the clockwise direction, the speed of the motor would start out slow and begin to increase speed as I turn the dial clockwise. Isn't that the way a speed control device should operate ?

So I tried reversing the Speed control black wires with the ends of the white motor wire I had cut, just to see if this would change the way the speed control worked, but this didn't change anything.

There are plenty of photos of the Top and Bottom side of the PCB and these can be magnified to get a real close-up view of the rectifier-diode , resistor and LED mounted on the PCB, the motor and wiring inside of the fan, in case you want to review.

What could be causing this reverse operation ? Looking at the traces on the Bottom-side of the PCB and relating that to the components on the Top side, do you think the rectifier-diode was installed backwards on the board at the factory ? Another thought, could the components inside the Speed Control have been assembled incorrectly at the factory ?

If there is no easy/cheap fix, I would rather use the Speed Control "as is".

I look forward to receiving your thoughts and ideas.

Thanks,

Todd

P.S. Your "Grab Bag" hasn't arrived yet, but that's OK........it will be exciting when it does !

CAS,
Guess what ! The light bulb finally went ON in my head. I checked the operation on one of my ceiling paddle fans and that's the way these Fan Speed Controllers work, for example, High Speed at the ON setting, then progressively slower as the speed setting is changed.

So, I'm back in business !

Thanks again for all your help !

ToddB66

[ToddB66]

Thread title: Need help determining Ohm value of resistor

Dear CAS,

Well, in one of my earlier posts I had decided to put the Hamilton Beach "True Air" wall fan back together and use "as is" without a speed control device, but after thinking about it and getting more answers from you I decided to go ahead with my original plan and splice the LUTRON Speed Control device into the fan circuit and I did that today. As I promised to report, the results were as follows:

Everything works, except the speed control dial operates in reverse. Starting with the dial turned all the way counter-clockwise to the OFF position , when I turn the Speed Control dial clockwise to the ON position the RPM's of the motor are at it's highest speed and then begin to slow down as I continue to turn the dial clockwise.

I would prefer that when the dial is first clicked ON in the clockwise direction, the speed of the motor would start out slow and begin to increase speed as I turn the dial clockwise. Isn't that the way a speed control device should operate ?

So I tried reversing the Speed control black wires with the ends of the white motor wire I had cut, just to see if this would change the way the speed control worked, but this didn't change anything.

There are plenty of photos of the Top and Bottom side of the PCB and these can be magnified to get a real close-up view of the rectifier-diode , resistor and LED mounted on the PCB, the motor and wiring inside of the fan, in case you want to review.

What could be causing this reverse operation ? Looking at the traces on the Bottom-side of the PCB and relating that to the components on the Top side, do you think the rectifier-diode was installed backwards on the board at the factory ? Another thought, could the components inside the Speed Control have been assembled incorrectly at the factory ?

If there is no easy/cheap fix, I would rather use the Speed Control "as is".

I look forward to receiving your thoughts and ideas.

Thanks,

Todd

P.S. Your "Grab Bag" hasn't arrived yet, but that's OK........it will be exciting when it does !

[ToddB66]

CAS,

Thanks again !

ToddB66

[CAS]

Dear CAS,

Am I correct that, when the speed control is connected to the circuit , the AC power is turned ON and the speed control dial turned all the way up, the motor RPM's will only reach the normal maximum running speed of the motor without a speed control device connected ? In other words, the speed control device can only lower the RPM's of the motor as I turn the dial toward the Shut-OFF position, but cannot raise the speed any higher than the normal maximum speed designed into the motor ?

ToddB66

Yes. Usually when the controller is on max, it will allow full voltage/current to the motor. The motor will only draw the current it needs.

[ToddB66]

Fan Speed Control Affect on RPM's of 1-Phase AC Motor.

Dear CAS,

As you know, I have an AC single-phase electric-powered Induction motor 120 V, 60 Hz, 0,14 Amp, Class B, driving a small squirrel-cage fan with activated charcoal filter, also a Lutron model FS-5F, 120 V, 60 Hz, 5 Amp max fan speed control that I am planning to connect in series with the motor to vary the fan speed (Photos attached for reference.).

Am I correct that, when the speed control is connected to the circuit , the AC power is turned ON and the speed control dial turned all the way up, the motor RPM's will only reach the normal maximum running speed of the motor without a speed control device connected ? In other words, the speed control device can only lower the RPM's of the motor as I turn the dial toward the Shut-OFF position, but cannot raise the speed any higher than the normal maximum speed designed into the motor ?

I know that for you this is probably like "beating-a-dead-horse", but I wanted to be sure my understanding of the speed control's affect on the motor RPM's is correct.

Thanks in advance for your reply !

ToddB66

[ToddB66]

CAS,

Thanks for your reply (post #33).

I'll be splicing-in the controller and will let you know how it works.

ToddB66

[CAS]

CAS,

Your last paragraph makes me a bit nervous about completing this project without burning anything up , but I do like your comment that "its basically just a variable resistor that will go in series with one of the fan wires."
I should have noticed early-on that the Speed Control must be wired in series, since the wires are both black ! I've installed enough toggle switches on the wall to know that they are connected in series on the black side of the power supply cable........shame on me and my apologies.

Regarding your comment "If I was doing the job, once connected I would be testing insulation resistance of controller to make sure there is no leakage to the exposed metal plate and double checking all connections with professional test gear", I've included two attachments with this post, one is a side view of the Fan Speed Control and the other shows the front of my meter. Now, if you magnify the Speed Control photo, it's easy to see there are pieces of white plastic tape between the black control housing and the exposed metal plate, nevertheless, I will test for insulation resistance using my meter set in the Ohms bell tone position. The photo of my meter is just so you can see the dial settings. That's the extent of my "professional" test gear, so "double checking all connections with professional test gear" really isn't an option for me I don't think.

Lets say I decide to risk it and connect the Fan Speed Control in series with one of the Fan motor wires. I assume both of these white wires are connected to the motor coil, so it doesn't matter which white wire I use for the splice....right ?

Having completed the splice, since you said earlier that "Your fan will only draw what it needs. The controller doesn't 'pump' extra current into the fan. The controller should be ok.", then I assume I can crank-up the analog Speed Control to it's max position without overloading the motor.......correct ?

Thanks again for your help on this project !

ToddB66

Note: when working with mains voltages NEVER assume wire colours are correct. I have seen all sorts of coloured power cables especially stuff made in Asia.

Any of the two wires will be ok.

when the controller is set to max, it is basically a short circuit so the fan will run as though it is connected straight to mains.

[ToddB66]

Using a 5 Amp Max 120VAC, 60Hz analog Fan Speed Control with a 120VAC, 0,14 Amp 60Hz Fan

CAS,

Your last paragraph makes me a bit nervous about completing this project without burning anything up , but I do like your comment that "its basically just a variable resistor that will go in series with one of the fan wires."
I should have noticed early-on that the Speed Control must be wired in series, since the wires are both black ! I've installed enough toggle switches on the wall to know that they are connected in series on the black side of the power supply cable........shame on me and my apologies.

Regarding your comment "If I was doing the job, once connected I would be testing insulation resistance of controller to make sure there is no leakage to the exposed metal plate and double checking all connections with professional test gear", I've included two attachments with this post, one is a side view of the Fan Speed Control and the other shows the front of my meter. Now, if you magnify the Speed Control photo, it's easy to see there are pieces of white plastic tape between the black control housing and the exposed metal plate, nevertheless, I will test for insulation resistance using my meter set in the Ohms bell tone position. The photo of my meter is just so you can see the dial settings. That's the extent of my "professional" test gear, so "double checking all connections with professional test gear" really isn't an option for me I don't think.

Lets say I decide to risk it and connect the Fan Speed Control in series with one of the Fan motor wires. I assume both of these white wires are connected to the motor coil, so it doesn't matter which white wire I use for the splice....right ?

Having completed the splice, since you said earlier that "Your fan will only draw what it needs. The controller doesn't 'pump' extra current into the fan. The controller should be ok.", then I assume I can crank-up the analog Speed Control to it's max position without overloading the motor.......correct ?

Thanks again for your help on this project !

ToddB66

[CAS]

By the look of the controller, its a basically just a variable resistor that will go in series with one of the fan wires. Now bear in mind that not all ac motors are able to be controlled by this type of controller.

Also remember that you are dealing with mains voltage. If you are not sure of something, dont do it.
If I was doing the job, once connected I would be testing insulation resistance of controller to make sure there is no leakage to the exposed metal plate and double checking all connections with professional test gear. Unfortunately there are too many electrocutions and fires caused from people performing mains voltage repairs/modifications/installations that they are not really qualified to do.

[ToddB66]

Using a 5 Amp Max 120VAC, 60Hz analog Fan Speed Control with a 120VAC, 0,14 Amp 60Hz Fan

You havent quite got that right. The controller will handle a max. of 5A. Your fan will only draw what it needs. The controller doesnt 'pump' extra current into the fan. The controller should be ok.

Hi CAS !

Attached is a photo of my LUTRON analog Fan Speed Control. You may have to use your magnifier to see up close and then drag left-right, etc. to see what you want.

You know, I remember that " Your fan will only draw what it needs" from a Home-Study course in Electricity and Appliance Repair I took years ago from NRI (National Radio Institute), but I wasn't certain if the warning (pasted in-part below in quotes.) applied to analog type continuously-variable Fan Speed Controls. My rationale for this was mentioned in paragraphs #4, 5 and 6 of my previous post, but from your reply in quotes at the top of the page, apparently the warning doesn't apply in this case.

" To reduce risk of fire or shock use only with fans rated 5 Amps max 120 VAC and marked suitable for use with solid state fan speed controls.".

I'm happy that you say my Fan Speed Control will work, but I need answers to the following questions if you don't mind, to bolster my "electronic newbie" confidence before going ahead.

Questions follow :

#1) I guess it goes without saying that I'm going to have to cut the white Fan Motor wires to splice-in the black Speed Control wires.........agree ?

#2) Since the wires from my Speed Controller are both black and the Fan wires are both white I would assume there are no polarity considerations when making these connections........am I correct ?

#3) After connecting the Fan wires to the Speed Control wires, can I twist the Speed Control knob all the way up (to the far-right) without burning out any of the Motor armature or coil wires ?

Thanks for your continued help.
ToddB66

[CAS]

You havent quite got that right. The controller will handle a max. of 5A. Your fan will only draw what it needs. The controller doesnt 'pump' extra current into the fan. The controller should be ok.

[ToddB66]

Wondered what my meters would read. Used a 1N4148 diode and two 1 percent resistors, 30 and 500 ohms. One meter has an extra digit resolution. Diode (.549v, .5948v)
30 ohm resistor (30.2 ohms, .022v, 30.24 ohms,.0222v) 500 ohm resistor (497 ohms, .321v, 497.5 ohms, .3122v). Based on your readings I was thinking the meter displayed the voltage with 1 ma current. (E=IR) It appears my meters use less than 1 ma and it's not constant. The diode reading changes with temperature.

Qiaozhi and green,

Just discovered I forgot to include you both in my post #27 when I thanked Thomas and CAS for their help.

Thanks much for your help too !

ToddB66

[ToddB66]

Question about testing a diode (Continued).

CAS and Thomas,

Attached are pictures of my fan, showing top and underside of the circuit board and the motor for your reference while reading the following.

To work with attachments, left-click once on each individually. To enlarge a specific area of the picture, use your mouse to hover the little enlargement dot over the area and left-click once. To turn off the picture, left-click the red button with white X in the upper-right corner of screen and when the pop-up dialog box comes up, click on the right-hand button that says "Close current tab".

I just noticed that my Lutron Fan Speed Control, model FS-5F with analog control dial has a warning stamped on the aluminum face plate that says "To reduce risk of fire or shock use only with fans rated 5 Amps max 120 VAC ", whereas my True Air Fan apparently draws only 0,14 Amps (read 14/100) as embossed on the back of the plastic Fan housing.

Since the speed control device is analog type (continuously variable ) with a 5 Amp max. rating , I assume that when the rotary dial is first clicked ON it is outputting less than 5 Amps, but likely more than the 0,14 A (read 14/100) embossed on the back of the Fan housing.

Hypothetically speaking, even if my Fan Speed Control outputs within safe running amps when the dial is at the low end just after clicking ON, I would need to put a safety- stop on the dial. Bottom line, I don’t think the 5 Amp max. Lutron Speed Control is a good match for my Fan. So, I’m going to use the FAN “as is” (without any speed control device) and see if it draws soldering fumes satisfactorily at normal speed, which I’m guessing it will.


Thanks to everyone who gave help in this thread.


ToddB66