old Thomas compressor

Does anyone know the CFM for the old (10-15 years old) Thomas compressors? Haven’t been able to find that info. Just wondering if it could be used as an off-computer only compressor.
Bob - Team 1308

CFM on page 2: ****Compressor Specs
It’s legal for use.


The duty cycle on the little new ones is not impressive. We’ve never had overheating with the old beasts.

Same here. We put a cooling fan on the little ones whenever we need the weight savings.

We are using the Thomas compressor on-board. It is 100% duty cycle. We tested fill rates against the two other compressors and it beat the am-3227 by ~15-20 seconds for 6 air tanks. We also tested the number of actuations of our main cylinder over the course of a normal match time with each compressor running, and we ended up with 6 more actuations using the Thomas compressor over the am-3227.

We are using 9 air tanks and looking to increase that. Our central boom is actuated by a 2" bore 24" stroke for both scale placing and climbing, so we can go through some air. We do have some other plans to reduce air and speed up the whole thing but they are untested and the robot is in bag. We thought of doing the work post Heartland but we were a little surprised that the jib/boom was 7-10 lbs more than we had thought it was after weighing.

One thing about the Thomas compressor on-board was that at week zero and when testing the blow-off valve (at 125 psi) I had the problem of burning up the 20A fuses. We did a current draw test later and it ended up being within a normal range. At 0 psig, starting the compressor drew ~10A and at 125 psig it drew ~17A. An older mentor told me another compressor we did have that they had tested was drawing in the 30-40A range and that they discarded it (and hoped we hadn’t somehow found another).

Anyhow, we switched the PCM from the PDP circuit with a fuse to a PDP slot with a 20A breaker (which is allowed). It saves you from being completely dead if the fuse blows and takes both the PCM and radio (VRM), and the resetting breaker allows the compressor to restart.

An ancillary issue we had in doing that is the 20A circuit breakers we got with the KoP are too long. We had a robot inspector stop later in our pit to check ours because they had noticed it with another team. At that time I hadn’t clipped them and only added a small piece of electrical tape to keep swarf from shorting the breaker. But after talking with the inspector we did end up clipping them because it seemed to be a reasonable change.

Team 23 reported to me that they found faster flow rates at lower pressures for some of their big cylinders. If you don’t need 60PSI for all tasks, consider a second regulator for a few jobs. This allowed them to use less air per cycle and still be faster.

We’re actually more complicated than that. We’ve designed a system with three air tanks at 60 psi in ‘reserve’ for our climb. We need that two-inch cylinder (or at least something nearly as big) to get our chassis in the air. But we’re thinking about going to a 1-3/4 (we’ve bought it already). Already have two regulators, run most of the match at 40 psi but then switch to 60 (with the reserve tanks) in the climb. We want all 60 psi then if we can.

The other thing Nelson alluded to is we’re thinking about going to one great big air tank. Airlift 12958 is listed at 2.5 gallons and reportedly weighs about 3.2 lbs, less than our nine clippards at 6.3 lbs total.

What do you guys know about this tank?