What's inside a SYNCHROSCOPE and how does it work

Today I explore the mysterious mechanism of an old synchroscope that was used to synchronize a power plant AC generator with the power grid (mains).

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[vaclavtrpisovsky]

Many synchroscopes also have two lightbulbs in parallel (for redundancy) connected between mains and the generator (which have a shared neutral connection). If they are flashing and the needle is twitching or not moving (in whatever position), it means that the frequency is way off. It is only safe to take the generator online when they are off and the needle is at 12 o'clock position. They are a cheap addition that makes operation less prone to error but are an epileptic hazard to some.

[MC-]

I can't imagine how much time and effort to put together analog meters such as this one especially the given limited technology back then, really appreciate the work from back then

[TheEmbeddedHobbyist]

As a young 15year old, we used to use 3 lamps connected between the 3 phases of the supply and the generator. We had to adjust the speed of the generator until the 3 lamps went out then throw the switch to connect them together.
The generator was about 1m long and 1.5m wide and driven by a very large motor. if the tutor left the room we would see who would throw the switch with the brightest lamps, the generator would try and rip itself out of it mount. 🙂
Once the switch the generator is phase locked to the supply and it’s very hard to change the speed of the motor driving it.
What fun we had in those days🙂

[jstro-hobbytech]

Very cool Dany. You continue to amaze me with the older technology which when explained seems like it shouldn't be obsolete.

[HugforYou]

i'm always amazed how these clever engineers were able to develop everything back then, but also had the knowledge how to produce it, i mean it looks good and solid, better than many that you can buy today. thanks Dany and kiss to your cat!

[ronliebermann]

A robot voice with a foreign accent. I guess the Italians are also going to have avatar bosses.

[Persanity]

From the other room my fiance yells "Was that english the entire time!?!"

[wdavem]

That's really nice! I recently noticed that you can see power plants falling out of sync in a video of the 2011 earthquake in japan; you can see the lights beginning to flicker faster and faster in sinusoidal fashion right before they fade out completely. As though perhaps a generator lost steam power yet was still on the grid! I'll post the link here if anyone's interested.

[vaclavtrpisovsky]

You could cascade two low voltage transformers to create another low-power 230 V to 100 V convertor (assuming you only have one variac). Then, you can try to sync an actual gasoline generator to mains!

[petrcibulak]

Thank you for quality content. Love the simplicity and principle of these devices

[vamoslafora]

that is a beauty device - I really like the way you explain and show these old devices

[SpeederXL]

Nice!
So simple and clever design. It will be interesting in the next episode to see it run on an inverter set to for example 49 or 51 Hz on one input and mains at the other. If you don't already have such an inverter, a simple way (since not much power is needed and the frequency range of interest is only within few Hz from mains frequency) is to use a speaker amplifier (and feed the input with a sine tone at the desired frequency, generated by the computer, an app on the phone or a function generator) and then connect the speaker output to feed a small iron core transformer
- which will rise the voltage from about 5-10 V (typically used to drive a 4 or 8 ohm speaker at about 1-10 W) up to 100 V or what's needed for the meter.

[fluffyblue]

For load transfer switching at the moment the supply's phases are in sync, indicator light bulbs will do just fine. For parallelling generators, this synchroscope will not only tell you when they are in phase like lightbulbs do. It will also tell you which generator is faster or slower than the other. And it is more accurate than lightbulbs.
For demonstrating this synchroscope, you can use a generator driven by a motor with speed control and try to sync that to mains. But if you happen to have an amplifier with vacuum tubes, you can just use a function generator. Take the output to the synchroscope from the primary side of the output transformer. Or use a transistor-based power amp and drive the secondary of a mains transformer to get a nice controllable sine wave at the primary.

[Timtron]

Great video about the phase Sync meter, they were used with marine engines and dual generators back in the day! Can you bring out the over-unity transformer / MEG unit and show everyone how to build it Sir. I found some old ballast transformer cores like you used. Thanks

[iamdarkyoshi]

Excited to see the next video. This thing's really neat!

[Leonards_life]

Thank You for a great video and explaination of the synchronism meter. I was an electrician in the navy and ran the generators and had to switch them on and offline on board ship.

[xDRTeK]

Wow! I heard of these but never seen one actually work. Thank you man!

[LeoLeoJR]

Very nice presentation. I was curious how this device is in fact is built inside and your movie shows everything in clear and simple way. Thank you for sharing

[SeanBZA]

Very important in a power plant, as putting a big alternator online with the wrong phase can be expensive. When online you adjust power output by controlling steam input, or fuel input for a diesel powered plant, as the alternator stays in sync with the grid, and extracts more power from the energy input instead of changing frequency, feeding it into the grid.

Quite a few incidents where a generation set got connected in the wrong synchronisation, and the result was at best a burnt out alternator winding, from it trying to put too much power in before the fuses blew, or in a few cases of the entire turbine and alternator exiting the building via the one wall and the roof. When they get connected the first time careful power plant engineers will have, in a set of disconnects on the grid connection, a set of 3 very high power resistors, so that in case of error, all that you have is a set of instantly burnt out resistors, and no damage otherwise. Once you are sure the plant is in phase, and correct you then can remove the resistor banks, and connect the links in place on the 3 bus bars. always possible to have a wire pair in a 3 phase system get swapped when installing, and this prevents this from being a very expensive and loud mistake. My father was involved in the civils side of a few power stations, and those repairs were both expensive and embarrassing to the ones who were in charge. Normally something drilled into them during training, make sure it is done correctly, and that there are measures to limit the fault current first time.

[iblesbosuok]

Analog mechanical multiplier!
Czech is a smart and meticulous country while Slovakia prioritizes the beauty of art. What a beautiful blend!