AM Compressor versus Thomas Compressor

[Mr V]

I found the specifications for the Thomas compressor here http://www.gd-thomas.com/product.aspx?id=12084&tp=p .

To summarize

Flow
Viair 1.03 CFM @ 0psi
Thomas .80 CFM @ 0psi

Max continous pressure
Viair 120psi
Thomas 100.1psi

Duty cycle
Viair 9%
Thomas Not rated

Max on time
Viair >3min 3sec
Thomas Not rated

Weight
Viair 2.4lbs
Thomas 4.4lbs

Outlets
Viair 1
Thomas 2

Current draw
Viair 10a
Thomas 10.5a

Check valve included ?
Viair Yes
Thomas No



Yes the external head temp of the Viair will get higher than the Thomas due to its lower thermal mass and the fact that it has more cooling fins to pull the heat from the compression chamber but that is a good thing since it likely means lower internal temps.

[Mark McLeod]

Originally Posted by Mr V

To summarize

Flow
Viair 1.03 CFM @ 0psi
Thomas .80 CFM @ 0psi

There's something wrong with the Viair spec sheet you used.
The Viair itself carries a label stating:
"Flow Rate @ 0 psi (13.8 volts): 0.88CFM"

The spec sheets of the two devices also do not appear to be comparable, because different criteria were used in the measurements, e.g., the VIair measurement is based on 13.8 volts, while the Thomas is based on 12v.

Somewhere around I have timed compression tests we ran with both the older Thomas model compressor vs. the VIair 90. I'll see if I can dig them up and post them.

[bardd]

I can't compare the technical specs (besides, it has been done 2-3 posts ago), but I prefer the new compressor. Its size and weight make it ideal for this year's smaller footprint, draws less power (never have we encountered electricity problems with it, unlike the Thomas compressor that draws so much power it shut our robot down in many occations) and makes less noise (which makes working withit that much more comfortable.

[Mark McLeod]

Here's a test that was run on the same system/same fully charged battery/different compressors.
System held pressure for 5 minutes after test.
Thomas 405ADC36/12 (from 2009 kit)
VIAir 90 (purchased through AndyMark)

Ambient temp: 68 degrees
Volume (including hoses/tanks): 360 cubic inches
Battery voltage at start was 13.6v. During compression the voltage was ~12.4v (+/- .1v). At the end voltage was 13.02 for both.

-----------Thomas --------- VIAir
Time --- psi/temp ------ psi/temp
0 min ----- 0/68d ---------- 0/68d
1 min ---- 60/70d --------- 30/69d
2 min ---- 85/71d --------- 60/72d
3 min --- 110/74d --------- 80/73d
3:31 ---- 118/74d (cutoff)
4 min ----------------------- 100/83d
4:31 ------------------------ 118/85d (cutoff)