Self Powered LED Bar Graph Current Level Indicator.

It should be fairly easy, yes.

I'm a bit surprised somebody doesn't have such a thing off-the-shelf. You could do one up from scratch, which may or may not be up your alley. If not, I've seen a few intellegent bargraphs that you might be able to couple to some existing bit of equipment and tweak it into doing what you want.

It's got to be a bar graph and not a numerical display? Murata makes a lot of really nice self-powered panel ammeters with digits.

http://www.murata-ps.com/cgi-bin/cd4power.storefront/EN/Catalog/1013

I am looking for a device powered by the current it is measuring, with no requirement for a power supply.

Check this link:

http://www.crmagnetics.com/products/Wire-Mounted-C29.aspx

I talked to these Guys and they did not seem interested.

Thanks for the reply.

Sounds like what you want is a panel-mount ammeter like this one from http://www.boatersworld.com/product/MP80814855.htm?utm_medium=productsearch&utm_source=google

If the needle is anywhere other than zero, then the motor must be running. An old analog style gage like this may not require a power supply. Newer LED styles would probably require a DC power source, portable types operate for years on a 12V battery.

EElectrician,

I tried an analog meter and the conditions are too rough.

Thanks for the link though, I can use those on the floating dry dock apps.

It sounds like a loop powered indicator.

Digital value loop powered indicators are commonly available, but are typically LCD (black on gray), not LED (colored), in order to minimize the voltage drop the device produces in the loop.

If suitable for use in northern climates, they'd have to work at low temperatures and be suitable for outdoor mounting, rain tight, etc. An integral junction box would be required, I'd think. There's seldom exisiting junction boxes at eye level on tanks.

Not knowing what is inside the one I used, I would have to say it is just an LED with the necessary dropping network connected to the c.t.

The vortex type pumps have a tendency to overload when there is not enough head pressure on them. If there were a way for an operator to watch a bar graph while throttling these pumps, without requiring anything other than a small enclosure on the cable.....

If someone could develop this, there is a definite market for it.

Go for it, and sell it to me when you get it perfected/patented.

How about just doing pressure measurement downstream of the pump? The current that the motor is drawing is of less significance than the pressure that it is developing, perhaps?

I would agree with your suggestion. It would be better to configure a pressure switch and a contactor to stop the pump before the current spikes rather than waiting for an operator to stop it after the fact.

Pressure or flow monitoring would be the way to go except this becomes complicated and expensive when pumping slurries.

I am looking for the least complicated method. Something I could offer to the customer at little or no cost to him/her.

I should have mentioned that these pumps are portable and flexible cord connected.

The LED bargraph elements would not have to stay on as the current increased, just the element representing the level. A color change (green, amber, red) would be ideal. Even a single multi colored LED would work.