Ammeter installation

K

Kevinmc

New member
I bought an ammeter from Ebay and want to hook it up to the dust collector to monitor my amp draw. The device is similar to this


Here are the instructions


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The instructions look like they are for a 120V circuit. For a 240V curuit should I
I run both L1 and L2 through the CT ring and should I connect L1 and L2 to the power connection.

Also I wonder if its dangerous to power this device with 240V since it doesn't look like its grounded and obviously not UL rated. Thanks

KC
 
Kevin,

I've purchased two of these as well and per the instruction sheet, you can connect the L1 and L2 leads to the voltage input connectors and also run them through the coil they provide. The unit is rated for 300 VAC and can detect 50 Amperes through the current transformer so you should not have any issue with the 240 VAC power to it. Since this meter is not drawing very much power, you can use light gauge wire for your connections (e.g., 16-18 ga lamp cord), but you'll need to use appropriate cord-style bushings into your dust collector control box.

I should also note that I have not yet connected mine up to my CV1800, but the schematic shown with the link you provided shows those connections. I paln to use one with my cyclone and the second one with my table saw circuit and will mount each of the meters in a 2-gang metal box with a two-position switch cover cut out to hold the meter.
 
For an ammeter connecting to a 2-wire + ground connection like this you only run one leg through the sensor ring. Otherwise the two legs will cancel each other and you'll measure zero amps, off or on.

Jim in Alaska
 
Thanks for the input. I have wired up the unit in a work box and will get it connected to the cyclone this week. I was thinking running both wires through ring might cancel out each cycle but didn't really put two and two together
 
I need to jump in again and pose a question to Jim, since I know he is an electrical engineer. Given that Kevin (and I) intend to get an accurate reading of both the voltage and amperage on our ClearVue cyclones, won't passing a single hot lead (L1 or L2) in a 10/2 wire cable passing through the sensor coil only provide an amperage reading on that leg? Wouldn't we get a full load amperage reading if the copper return wire was passed through the coil? I'm fairly confident that we will get 240 VAC displayed by connecting the volt meter leads to L1 and L2, but the amperage with just L1 or L2 passing through the sensor coil will just detect half of the load, right?
 
The motor uses only two wires in the overall motor circuit(L1 and L2). Whatever current flows into one lead comes out the other. If there is a difference in those two currents there is a short or leakage to ground in the motor. The green wire connects only to the motor frame, not to the motor circuit. So the current reading in one wire is the same as in the other wire except for direction of the current.
bababrown
 
Thanks -- I should have figured that out -- it make sense as deep down I knew that the bare copper wire could not be a current carrying conductor.
 
Ammeter readings

Ammeter readings

I have put 3 of these meters into my shop. The results are interesting.
My CV1800, is not doing much work at all.
Peak In Rush is around 96 amp vs. the locked rotor 107 amps.
With no gates open, 7.0 amps
My furthest 6" gate open 10.8 amp
I have one 6" gate on a wye about 10ft from the cyclone entrance with nothing after the gate. With only this gate open: 11.2 amps.
I have one leg with a 4" port. With only this port open: 9.6 amp
My cyclone is the 2007 design. The only enhancement is the gore block.
I have 2 Camfill-Farr Hemipleat filters on the exhaust.
I have not measured current draw without filters.

Based on amp draw, something is not as good as it should be. Leaks are not factored - leaks would be good.
Impeller is turning in the correct direction - CCW looking at the motor from the cyclone (shaft end)
The difference in draw between no gates open to one 4" is 2.6 amp
The difference in draw between no gates open and the closest 6" is 4.2 amp.

I have 2 other 5HP motors in my shop. On my 36" bandsaw there is a 1735 rpm Baldor which peaks at 107 amps, then lines out at 9-10 amps once running, the other is a no name on a 16" Laguna planer. It comes up to speed quickly and only draws 3 amp no load.

There must be a way to correlated amps and CFM in a 6" circuit.

Any thoughts?

Don
 
Don,
Do you have photos of your install in the gallery? Also, are you significantly above sea level? I have to believe that the fan is being starved for air at the input or restricted at the output (or both). Have you measured airflow with a pitot tube?
Bababrown
 
Richard,
Thanks for the quick response.
No photos yet. My elevation is +624m or 2050 FT
Just finalizing connections, so have not done any other measuring.
I will disconnect the filters tomorrow, then figure out what is next.
Is there any particular clearance between the fin edges of the fan and the housing that should be observed.
Don
 
Don,
The air density at 2050 ft is about 0.93 that at sea level so you will develop a little less power. But I think your amperage numbers are well below what I would expect. Most of us see around 17 amps max.
bababrown
 
I shall try and pick up a pitot tube and a magnehelic gauge this week.

UPDATE
Actually, I will get a hand held anemometer. Sounds like they are the way to go these days for convenience and reasonable accuracy.
 
Last edited:
Anemometer Update

Anemometer Update

I did acquired a little hand held anemometer. My 6" run to my bandsaw is reading 4400 - 4500 FPM at the saw. This gives me over 800 cfm at that point which is our target. :)
Once I get my ducting secured and joints taped, I will do some proper measurments and recording. As well I guess I should get some photos up.
 
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