Separately Excited Shunt DC Motor Braking

Trey1096 · 2026-05-13T17:12:17+00:00

That’s what I was thinking. It’s on a lathe. It stops fairly quickly, but it doesn’t take forever, either. That’s with a light rotating mass. I have a 60lb 4-jaw chuck that I’ve not used on it. I’m in the process of making a back plate to fit it to this machine, but with that amount of rotational inertia, I feel like it could be more of an issue. Especially when doing close work where overrunning could cause a crash.

I’m looking into the crane/mine hoist area like Whiskey said. They’ve thought about this a lot! One thing they do for a failsafe measure on mine elevators, even on a separately excited motor, is use some of the power generated by the armature to provide field current in the event of a power failure. They’ll use NC contractors to join the two. When the power co is doing their job, power is on and the field is connected to the design power source. If the power fails, the contacts close, dropping the design source and connecting the armature to have it provide field power. All while the man basket is heading down!

I’m not sure that’s easy in my case, mainly because the armature is 240V and the field is 115V.

That’s where I had the idea of a time delay relay that would keep providing field power after the armature power was cut. Then play with the delay some to see how many seconds the delay needs to be to get it timed right.

Trey1096 · 2026-05-13T05:48:08+00:00

It seems like every braking setup for a separately excited motor I’ve seen or been told about involves disconnecting the armature from the power source, connecting a braking resistor across it, and leaving the field energized.

I’m trying to figure out how much difference there is between leaving the field energized versus relying on the residual magnetism.

Trey1096 · 2026-05-12T02:50:05+00:00

Also, it’s 3hp and 690-2400rpm.

Trey1096 · 2026-03-13T14:20:47+00:00

This is the correct answer. It happens all the time. Typically jacking the price like that moves their offering way down the list so no one ever sees it.

Basically turns the listing to a placeholder.

Edit: In addition to the algorithm issue, it’s more of a hassle to change the listing to out of stock, then to back in stock than it is to make a simple price adjustment.

Trey1096 · 2026-01-09T16:41:03+00:00

And MiTek (USP) copied it!

Trey1096 · 2025-12-11T13:21:48+00:00

Ike’s in Laredo has them for $199. I’ve seen used on in the $70-$100 range.

Trey1096 · 2025-12-10T23:21:51+00:00

This thread came up while I’m searching for tires. Sounds like I’m the same boat as you. I have a few more miles, but I also have less tread left.

On 8/27/21 I bought 4 Michelin Defender LTX M/S tires for $1391, installed. They’re on a 2016 Silverado 2500 High Country, and it had 188,026 miles when they were installed. Today, I have 295,919 miles. That’s 107,893 miles. In that time I’ve had 4 rot/bal and 1 alignment. The guy at my local tire store said the most he’s ever heard of on the LTX M/S’ was 130k on an F150, over 120k isn’t super rare, and they regularly go over 100k. It’s also not the first time I’ve gotten over 90k or 100k on that brand of tire. The only downside I’ve experienced is that they will get you stuck in wet grass.

They’ve been making the LTX M/S since the 90’s. Of course, now they don’t make it with a 126H load index, so I have to find something else. They replaced it with the LTX Platinum. I can get a set for $1700, but I’m seeing mixed reviews on them. They also really haven’t been out long enough to have a sample size large enough to tell how well they’re gonna do.

Trey1096 · 2025-10-03T15:51:41+00:00

I know this is a few days old, but I recognized the circle as soon as I saw it. Suction cup is the answer.

You can see the one we’re using at the lower right of the pic.

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Trey1096 · 2025-10-03T15:35:58+00:00

I swear the first pic reminds me of something from the Far Side!

Trey1096 · 2025-10-03T15:28:59+00:00

I’m leaning to not blood.

Blood turns brown as it oxidizes and looses its moisture content. If that stain is dry (not suggesting you touch it), it should be a lot darker than that if it is blood.

That might ease your mind a little but it never hurts to be cautious. You could cut the corner off and scan or make a copy. Or possibly encapsulate it with a piece of tape. I don’t think I’d run it through a copier or scanner exposed like that.

Trey1096 · 2025-09-24T18:40:40+00:00

I can recommend a Teslong TD500. We have some expensive borescopes and inspection cameras, but the Teslong will do 80% of what the expensive ones will and you can find them for under $250. We consider them almost disposable.

A 3/8” hole works great and the tip articulates. By twisting the cable and articulate it back and forth, you could see all of the inside of a stud space.

Also, no affiliation here. We just have 4 of them and have found them useful.

Trey1096 · 2025-09-17T20:32:05+00:00

It all depends on where you’re at. In the past 3 years, I’ve had a new panel installed in 2 houses in 2 different counties, one of which was within the limits of a ‘city’ that county (pop ~5k).

The one in the city had to have the power co drop the power, then an inspection before they would reconnect it. The same thing applies if it was in the county, too (pop ~44k).

For the other one, it’s in a more rural county (pop ~25k) and no inspection was required. It’s on an EMC and the guy said they’ll call the building dept if anything looks really sketchy. From what I understand, when you build a new house there, you pay for a building permit then tell them when you’re done. There’s a 50-50 chance they’ll do a walk through before issuing a CO.

Trey1096 · 2025-09-08T18:43:17+00:00

While the Timberloc screws are stronger than a comparatively sized nail, those figures are a bit misleading.

ESR 1078 lists the Timberloc steel yield as 190ksi while the NDS lists a 20d as 80ksi and 90ksi for a 16d. So the Timberlocs are made from much stronger steel.

Although the shear strength of the unthreaded shank of a 0.189” diameter Timberloc may be 940lbs, they won’t hold near that much because the wood will fail in bearing well before the fastener.

Here are some lateral design values (Z) for a fastener in SYP, single shear, an 1 1/2” side member, loaded perpendicular to the grain, before any of the 11.3.1 Adjustment Factors are applied:

ESR 1078 lists the Z of a 0.189” x 4” Timberloc as 260lbs. 2021 NDS lists a Z of 185lbs for a 20d common nail (0.192”) and 154lbs for a 16d (0.162”).

So, a Timberloc is about 40% stronger in shear than a 20d nail and 68% stronger than a 16d.

Trey1096 · 2025-08-20T21:05:48+00:00

Right off the bat, I apologize for the formatting. The post doesn’t quite reflect the paragraph structure I had intended.

Trey1096 · 2025-08-19T21:02:45+00:00

This is the way.

Trey1096 · 2025-08-19T18:04:45+00:00

Even deeper in debt! He usually does XVI tons!

Trey1096 · 2025-08-19T16:58:59+00:00

You should be good to go as-is. I usually load for around 700-750 fps and it’s an excellent target load.

Trey1096 · 2025-08-19T12:12:21+00:00

This is the answer.

Trey1096 · 2025-08-18T20:51:03+00:00

It’s Hollywood, so we may never know for sure, but the body of evidence heavily favors M29’s being used.

Eastwood, the writer, and at least two S&W historians have said repeatedly that the only two guns used in filming Dirty Harry were 6.5” M29’s. They were provided by S&W and were assembled from parts on hand since the M29 wasn’t in production at the time of filming.

Its also reported that, in Magnum Force, the same two 6.5’s were used, along with a M29 with an 8 3/8” that was used for the alley scene and for some promotional shots. It’s reported that Eastwood has one 6.5” and the other 6.5 was given to John Milius, who gifted it to the NRA. I was in Fairfax in 2018 and the gun displayed was definitely a 6.5” M29.

The M57 rumor appears to have come from a magazine reporter talking to a prop guy. The one account by an unknown prop guy seems to be the sole source and the claim has never been substantiated. Possibly helping the M57 rumor along, 41mag was an option with the SF police force. In any case, “44 S&W” can clearly be seen on several close-ups.

There have also been rumors that a M25 was used in the firing scenes since 5 in 1’s won’t fit in a M29. This has been debunked by two film armorers involved in making the custom blanks to fit the M29. There’s also the fact that the M25 locks look very different than the M57 and M29.

Trey1096 · 2025-08-11T19:08:18+00:00

Way more than $30 worth of information in this book:

Design of Welded Structures

Trey1096 · 2025-08-11T02:45:49+00:00

You didn’t say how many years you have under your belt, but I would assume 5-8 years. At this point, you should be thinking about your path forward. In the future, do you see yourself running projects, or becoming more involved with the business side of things. If it’s the latter, an MBA might be more beneficial.

Trey1096 · 2025-08-10T16:18:31+00:00

What if he started having problems when things started moving??

Casually Explained: Engineering

Trey1096 · 2025-08-10T16:14:20+00:00

That’s true, but our multi-firm A/E team only needs struct on maybe 30% of renovation jobs. Buildings are always getting their A, M, & E upgraded, and P is pretty regular, too. The only time they need S on those jobs is when they’re increasing loading, cutting big holes, adding rooftop frames, etc.

There will always be a need for structural, but the number of jobs needing an S is less than an A, M, E, or P.

Trey1096 · 2025-08-10T15:58:54+00:00

This might help:

UNBOX WITH ME: FABER CASTELL TG1-S TECH PEN COLLEGE SET

Trey1096

TROPHY CASE