Re: FC350BJ/110V Controller Transformer and Switch Failure.
Thank you all for the feedback. I haven't devoted any real time to work further on this project, but wanted to acknowledge?
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I didn't notice a thermal fuse bump on the transformer.? But it's on the bench in the office, and I may start to remove the insulation tape.?
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When the transformer was removed from the board, I did check the MOV.? It measured high resistance.? The MOV part number is 471KD10, e.g. 470V typical.? ?Min is 423V, and 423/sqrt(2) is 299V RMS max.? Of the cuff, this seems too high to be of any real benefit in a 120V mains AC application.? ?For added piece of mind, I will use an external surge protector.? (I did use one most of the time)? I have other unvetted speculation ideas too.? The hobby machine's electrics weren't designed with best known practices (>$).? ?
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Maybe my problem is indeed a one-off and not a common problem with the FC350BJ/110V Controller in the MiniLathe community.
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Regards,
Gary
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Re: FC350BJ/110V Controller Transformer and Switch Failure.
Weird fault.? Very uncommon for a transformer primary to die, they often have thermal fuses which fail.? They’re supposed to fail if the transformer overheats (Hey Dave, sound familiar?) but occasionally die just because they feel like it.? ? You’ll find it if you cut away the insulation tape, you might see a little bump.? If the primary is ok replace (or bypass) the fuse.? If replacing remember to crimp in the new one, don’t solder it.? Trap for young players, everyone does it once. ? The MOV isn’t strictly needed.? They suppress spikes by shorting out (and getting warm).? They eventually fail by staying shorted and then take out the fuse.? Spikes shouldn’t bother the transformer but definitely bad for the electronics.? Repeated spikes might have taken out the thermal fuse. ? In theory bypassing the thermal fuse and removing the MOV would get it running again until you can fix it properly. ? Bad switch on the pot is strange as well, might be coincidence. ? If the machine was plugged in but switched off (via the emergency switch), then all of those components would have been isolated from spikes on the line. ? I’ve no idea what went wrong, but good to see you fixed it easily. ? Tony ? ? ?
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From: [email protected] <[email protected]> On Behalf Of Gary Anderson via groups.io
Sent: Sunday, 2 March 2025 3:40 am
To: [email protected]
Subject: [7x12MiniLathe] FC350BJ/110V Controller Transformer and Switch Failure.? I have the FC350BJ motor controller on my Cummins mini-mill.? It is also used on mini-lathes so this applicable to this forum.? It's a second hand machine so I don't know its history.? ?Motor/controller was running as new.? Machine was unplugged and not used for a few weeks.? Plugged her back in and the motor would not turn-on.? The switch portion of the potentiometer/ switch was faulty.? In the CCW position the switch should be closed.? I had ~1 Meg Ohm of resistance.? The transformer for the low voltage +15V, -15V? circuit was open on the primary side.? Luckily LMS eventually had these parts in stock. LMS Part# 2492(Transformer), #1282 (Potentiometer).? ?I am grateful for their sourcing of replacement parts.? After replacing the two known faulty components, the mill now turns-on with full range speed control.? I have not yet tested under motor load. I understand that the potentiometer will eventually wear out. The fact that LMS carries the transformer leads me to believe that this is a somewhat common problem with this controller.? I did not find anything on the web about this particular problem.? Hence one reason why I am posting here.? Maybe help out another person that has experienced this fault.? Right now, my only brainstorm is there was a power surge when the pot/switch was in the CCW position.? The Metal Oxide Varistor didn't clamp and protect transformer, but it did clamp and drew more current than the pot/switch could handle. I have not yet replaced the MOV on the PCB.? ?I haven't completely thought through the problem, yet here I write.? Does anyone here have advice on other components that may be faulty/compromised that lead to burn-out of the switch and transformer?? Or modifications that can be done to make this controller more robust that are worth the time and money??? Resources that I used to assist me during my debugging: For now, the mill is up and running.? I am still eyeing the KBMD-240D as a more robust alternative.
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Thanks?
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The link to the manual is very helpful, and I had never used the Drafts button despite using Groups for years! ?I know to use it now. I had assumed it would require you to specifically save a draft, but apparently does it automatically. Good tip, thanks.
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(Didn't get any interest in the Polygon cutter though!)
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Evan
Lathe: 1955 Boxford Model A with screw cutting gearbox, power feed with several accessories, hand tools and a pillar drill press.
Try my Free Online Gear train Software:
You enter a thread pitch or TPI and it shows you a range of gear trains and gearbox setting to use and even a scale drawing of the gear train.
It also includes calculations for taper turning by the tailstock offset method, and cutting speeds.
It includes the specifications for many thread types eg metric, UNC, BSW, and BA.
Displays drill sizes for tapping threads at any percent thread depth (with full explanations).
My YouTube Channel and Playlist about using an engineers lathe: ?
Project to build a Greek Hero steam engine and measure its power output:?
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Re: FC350BJ/110V Controller Transformer and Switch Failure.
RUD failure.?
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For those who might not have heard the term before it's referred to as Rapid Unexplained (Unexpected/Unknown/Unscheduled) Disassembly (Decompression/Disembowlment) and so on.? I don't actually know of its etymology but was once told it came from the military or quite possibly somewhere in the space race industry (or I heard it in a movie).
tldr; think of it like a very fast reacting fuse where every time the breakover current is exceeded a micro fissure or 'hole' is created in the substrate and eventually it's weakened enough (swiss cheese) that it either explodes (if you're lucky and all the visual inspection artists point it out rather quickly because all the smoke gets let out) or it just dies; doesn't wave a red flag-just sits there looking pretty.?
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-Me: trying to put the "fun" back in electronics.... because aren't 3 letter words supposed to be exciting??
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Re: FC350BJ/110V Controller Transformer and Switch Failure.
Replace the MOV! They suffer internal damage whenever they clamp. Here's an insomnia curing paper on the subject;
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?< >
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To minimize future problems, consider powering the lathe from a surge protected power strip instead of plugging it directly into an outlet.
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Roy
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Re: FC350BJ/110V Controller Transformer and Switch Failure.
The wiring diagram for your controller can be found on LMS: ?.? It shows that both sides of the AC line are switched.? It would require a pretty substantial spike on the power line to take out the switch AND transformer!
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It definitely would be a good idea to check out the MOV
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FC350BJ/110V Controller Transformer and Switch Failure.
I have the FC350BJ motor controller on my Cummins mini-mill.? It is also used on mini-lathes so this applicable to this forum.? It's a second hand machine so I don't know its history.? ?Motor/controller was running as new.? Machine was unplugged and not used for a few weeks.? Plugged her back in and the motor would not turn-on.? The switch portion of the potentiometer/ switch was faulty.? In the CCW position the switch should be closed.? I had ~1 Meg Ohm of resistance.? The transformer for the low voltage +15V, -15V? circuit was open on the primary side.? Luckily LMS eventually had these parts in stock. LMS Part# 2492(Transformer), #1282 (Potentiometer).? ?I am grateful for their sourcing of replacement parts.? After replacing the two known faulty components, the mill now turns-on with full range speed control.? I have not yet tested under motor load.
?
I understand that the potentiometer will eventually wear out. The fact that LMS carries the transformer leads me to believe that this is a somewhat common problem with this controller.? I did not find anything on the web about this particular problem.? Hence one reason why I am posting here.? Maybe help out another person that has experienced this fault.?
?
Right now, my only brainstorm is there was a power surge when the pot/switch was in the CCW position.? The Metal Oxide Varistor didn't clamp and protect transformer, but it did clamp and drew more current than the pot/switch could handle. I have not yet replaced the MOV on the PCB.? ?I haven't completely thought through the problem, yet here I write.?
?
Does anyone here have advice on other components that may be faulty/compromised that lead to burn-out of the switch and transformer?? Or modifications that can be done to make this controller more robust that are worth the time and money???
?
Resources that I used to assist me during my debugging:
John Gerling's write-up
https://olduhfguy.com/
?
For now, the mill is up and running.? I am still eyeing the KBMD-240D as a more robust alternative.
?
Regards,
Gary
?
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yea , the guy does real nice work . I wish I had half his
patience .
On 2/28/25 6:36 PM, Ryan H via
groups.io wrote:
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I watched a lot of his build
on the QC.? Pretty nice job IMO.? Way above my pay grade,
LOL!?
A bit ago there was talk on QCGB's , this
guy made one for a larger
lathe & has several youtubes on his
build .
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I watched a lot of his build on the QC.? Pretty nice job IMO.? Way above my pay grade, LOL!?
A bit ago there was talk on QCGB's , this guy made one for a larger
lathe & has several youtubes on his build .
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A bit ago there was talk on QCGB's , this guy made one for a larger lathe & has several youtubes on his build .
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You have a lathe, no need for the grinder On Thu, Feb 27, 2025 at 10:28?AM Jacques Savard via <jacquessavard= [email protected]> wrote:
pl
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what? do you? thing? about? use? a? grinder? to make a poley? whit? the nut
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is it a good? or bad? ?way? to fix? my problem?
?
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some body? do that? before ?
?
jack 47 71
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pl
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what? do you? thing? about? use? a? grinder? to make a poley? whit? the nut
?
is it a good? or bad? ?way? to fix? my problem?
?
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some body? do that? before ?
?
jack 47 71
?
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plisse, voraite in french aiv' ry bodi antersdand.
tink u
On 22.02.25 21:38, Jacques Savard via
groups.io wrote:
toggle quoted message
Show quoted text
?
ok
I think? I have x2? solution
1- make polly? whit? the? nut? very lilltle? poly? about 1
inch?
2.-? the? shaft are abour 5/8? inch? and? I? have? ?poly of
1/2 inch? inside? but? not? able? to make it? fit? on this kind
of? shaft
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phot? show? all? the problem?
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some? solution? maybe
?
?
Attachments:
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?
ok
I think? I have x2? solution
1- make polly? whit? the? nut? very lilltle? poly? about 1 inch?
2.-? the? shaft are abour 5/8? inch? and? I? have? ?poly of 1/2 inch? inside? but? not? able? to make it? fit? on this kind of? shaft
?
phot? show? all? the problem?
?
some? solution? maybe
?
?
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Re: Here list of charts & Tables
Add a few more pages on making?
- PISTON RINGS
- MILLING IN A LATHE?
- MAKING GEARS IN A LATHE?
- BORE A ENGINE CASTING ON A LATHE
- DRILLING A LONG BAR IN A LATHE?
- and more
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Dave
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Part 1 of 2
Part 2 of 2
?
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see link for more
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/g/minilathe/files/6.%20Rarely%20used%20Charts%20and%20tables/1%29%20How%20to%20books%20and%20files/1%20piston%20ring%20milling%20gear%20cutting%20and%20more.PDF
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I did not see last September.?
I think most mini lathes have a 3" or 4" 3 jaw.?
I do not know swing of your lathe.
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The first did after the tool post was get a 5" 4 jaw chuck for the larger parts also a 4 jaw will grip a little larger too.?
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My 5" 4j will grip around 6" .
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If find used 6" 4j it will do around 7"
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Dave?
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On Thu, Sep 19, 2024 at 02:09 AM, David James wrote:
It is a 2 cylinder double sided beam engine. A bit too big for my small machines, I will try to attach the plan
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Re: A new (and slightly off) topic
Agree with mike in snowy Kansas.
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All kinds of materials are machined.
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Wood is nothing of a mess compared to phenolic.
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Consider using a vacuum when working with messy material.
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John (in very cold Michigan -it's 4 degrees at this writing ; )
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Re: A new (and slightly off) topic
Just my 2? worth this morning.....
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I really don't think this thread is off-topic.? We are talking about machining different materials on a mini-lathe.? Does it really matter what the material is?? Would it be off-topic if I said I was cutting threads on a Delrin? ring for a telescope lens?? Is it off-topic if I am making a Teflon? piston for a replica steam engine??
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In my main hobby of restoring antique carousel organs, I once made a production run of 600 "pipe toes" out of birch.? These are small to medium turnings that have a through hole, a tenon, and need a very repeatable taper of 3°.? My 8x14 mini-lathe was the only appropriate machine in my shop.
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For those of you who like to google more information, here's an article from my good Friend David Wasson (who is a machinist by the way):
https://coaa.us/index_archive/Issues_31_to_40/Traditional%20Band%20Organ%20Pipe%20Construction%20-%20David%20Wasson_%20_35%20&%2036.pdf
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From snowy Wichita Kansas,
Mike
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Re: A new (and slightly off) topic
Having precisely milled wood blocks on my mill I would say "Go for it!"?
On Sat, Feb 15, 2025 at 1:08?AM davesmith1800 via <davesmith1= [email protected]> wrote: This very clear this site is only? MINI LATHE.?
So remember no off Topics here
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I can help just send message I think i have seen your name on
?and can help you out the first is on engines and steam engines.
The message system works best on
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Here I only talke about mini lathes?
I would post email but that is not good idea today.?
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Dave?
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Or use a real email client 8-) [gdr]
I don’t have that problem…even If I close the mail without sending it asks me if I want to save the draft…has saved my butt multiple times.
Of course my day job in IT kinda drilled it into me decades ago… On Feb 17, 2025, at 12:36?AM, Jon Rus via groups.io <byghtn5@...> wrote:
You could type your message into the
windows notepad, or something similar, and copy + paste into the
web pages......
On 2/17/2025 1:23 AM, Evan via
groups.io wrote:
?
Hi Ron,
?
Yes I do that SOME of the time. The problem is I keep
forgetting to make a copy. Other software, like text editors
don't do that, so I only have to remember when using online
stuff.?
?
Evan
Lathe: 1955 Boxford Model A with screw cutting
gearbox, power feed with several accessories, hand tools and a
pillar drill press.
Try my Free Online Gear train Software:
You enter a thread pitch or TPI and it shows you a range of gear
trains and gearbox setting to use and even a scale drawing of
the gear train.
It also includes calculations for taper turning by the tailstock
offset method, and cutting speeds.
It includes the specifications for many thread types eg metric,
UNC, BSW, and BA.
Displays drill sizes for tapping threads at any percent thread
depth (with full explanations).
My YouTube Channel and Playlist about using an engineers lathe:
?
Project to build a Greek Hero steam engine and measure its power
output:?
--?
Bruce Johnson
The less a man knows about how sausages and laws are made, the easier it is to steal his vote and give him botulism.
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Evan
davesmith1800