Looking for Line Frequency Monitor. 6

[itsmoked]

I've tried all the search subjects I can think of and have found lots of really nice phase-loss protection relays but not a single one will trip on frequency deviation. You'd think no one used non-utility power.

Does anyone know of a line freq monitor?

240V, 3ph, no neutrals. It can, of course, be just a single phase.

It will be used to inform a PLC.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[ScottyUK]

Hi Keith,

Ever come across this company before?

https://www.novatechweb.com/power-measurement/bitronics-products/

Bitronics has been taken over since I last used their products, but the current range looks like it would do what you're looking for. Apologies for the slow reply, I was struggling to remember the name.

 

[Sparweb]

Late to the party as usual...
If you're keen to DIY: I built something like this with an Arduino.
Mine is datalogging/LCD display only, but there isn't a big trick to making an Arduino drive a relay.
The hook-up is dead simple; just need an Arduino with 3 interrupt pins (eg. 2560 Mega) to trigger at the zero-crossing of each phase.
PS my Arduino board ran throughout the -25C to -35C deep freeze we experienced for a week 100% perfectly.


STF

 

[LionelHutz]

If you want power metering then an Accuenergy Acuvim-CL-M-5A-P1 could be had for <$250. Accuenergy meters sell from multiple places online so they are readily available. Pull the voltages, currents, frequency and power data using the comms port and then you can do whatever you want with the data in the PLC logic. It's not a protection relay though, so you'd have to program any protection functions in the PLC. If you want to get fancy, you can get a version with a nice display for more $.

I don't know the best place to buy cheap current transformers as a consumer. I expect you can find 75:5A or 100:5A CT's for around $25 each?.

 

[itsmoked]

Well I'm back from $11.52-per-day-full-size-2018-rental-car-with-700-miles-on-it-Spokane! In my town a compact at the same rental agency is $52/day. The asphalt square I parked my car on at the airport in Silicon Valley cost me $18/day!!
Remind me not to take flights that require I get up at 3:30AM. Cripes!

Freddy; That looks pretty good. Unfortunately this car has a pretty good auto-start system already. A second car we're specifically having an auto-start problem with might benefit though!

Bill; You slipped a cog.. What unit at Automation Direct?
This one? (colorful)

If so, Funny! I've installed about 3 of those in the last two years. Never paid attention to the tach mode.
Scotty: Thanks. I can see why that would be hard to remember.. They look very nice but probably pretty pricey. :/

Hi Spar: Good to hear that your Arduino weathered that. I'll consider them a little more. Not sure that will fly for this $2M machine though..


LionelHutz; That is a crazy spectacular product for the price! It's a strong contender.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Sorry. Yes, that family of instruments. If the previous installs were successful you may be willing to recommend that unit.
Once I realized that you were concerned with NON-electrical events causing a slowdown I realized that load monitoring would not give the protection that you need. You have to look at frequency or speed.
You mention governor issues as a possible event. I have seen more than one engine go Wide Open Throttle as a result of governor failure. (The last time was a wild WOT ride on a 30+ year old swather while cutting hay for William's horses.)
Set a high alarm as well as a low alarm. Starting one of those big A/Cs may cause a momentary, but not system threatening under-speed as well as an over-speed on recovery. Consider a short time delay to avoid nuisance trips.
A silly is stuck in my mind.

pathological sage brush

I can't help but wonder;
Is that the sage just downwind of the peyote cactus patch or has a sage germinated in a mushroom bed?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

It's the peyote ones that pile up on the rails and then bounce up getting into the works!

Wild WOT rides... Clearly you should have video running on everything you do. You could pad out your income with a Youtube channel of fun.

You make good points on the time delays. I'll check if those tachs can watch 16ms stuff usefully. Since the rendered signal goes to a PLC I can easily do blanking for momentary events. Thanks!

Keith Cress
kcress -

http://www.flaminsystems.com