Andymark 1.1 Compressor Data

[GeeTwo]

Originally Posted by Alpha Beta

Don't mean to sidetrack the discussion too far here, but...

What do you mean "usually set the switch"?

We still use the adjustable switches during practice and for demos, which use a lot more air (over the course of hours) than the competition robots. Use of the preset 115s during competition is offset (or more than offset) by doing fewer cycles per hour.

[cbale2000]

Originally Posted by GeeTwo

Does anyone have any good gouge on the duty cycle of the Thompson compressor referenced above? None of the web pages or data sheets listed it. Unless by "continuous" in some labels they mean 100%? If so, the Thompson would outperform the 1.1 in a demo/practice mode, and in many cases in competition mode. That would also explain the much higher price.

Continuous = 100% duty cycle, at least in the case of the Thompson.

[Richard Wallace]

Originally Posted by cbale2000

Continuous = 100% duty cycle, at least in the case of the Thompson.

The compressor mentioned earlier in this thread is the Thomas (not Thompson) model 405ADC38/12, which was the standard FRC kit compressor for many years. That compressor is definitely NOT rated for 100% duty.

Its motor's rating is ~75 Watts, so it can draw 75/12 = 6.3 Ampere continuously. This is significantly less than the power consumed when the compressor is running -- then it draws about 11 Ampere, so it is consuming 132 Watts.

Some of the power consumed actually compresses air, and the rest is lost as heat in the motor coils, or as friction in the pump, or in other ways. If the compressor's continuous rating is limited by the size of the motor, then its duty will be about (6.3/11)^2 = 33%.* However, most compressors of this type are limited by the size of the pump; experience with this compressor in FRC application suggests its duty limit is less than 33%.

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*Motor heating is roughly proportional to the square of current draw, because most of the heat comes from resistive losses in the coils.

[Chris is me]

Good enough for me. I'll take lower current and faster fillups any day of the week. Unless this is significantly slower at 60 PSI and the others are not, this seems better for our application than the viair which isn't great at topping off tanks.

[Kevin Sheridan]

Originally Posted by muffinofsteel

My team isn't too terribly pneumatic-heavy, unlike the cheesy poofs(see their 2014 robot). We also store air before the match, and try to avoid running the compressor constantly during a match. A way we get around not running it constantly is having more air tanks, giving us more air to work with between the compressor turning on.
Out of curiosity what compressor did you use last year, and how often were you actuating cylinders?

IIRC we used the smaller thomas compressor. We only used 3 tanks and the only air intensive actuation we did was lowering and raising the utility arm. Sometimes we avoided the CDF for a cycle to let our tanks charge a little more since doing the CDF could require 3 actuations (raise-lower-raise). This was an unusual situation since normally we would throw more tanks on but we didn't have the space or weight to do so this year. That being said the only time where we truly felt like we didnt have enough air is when we smashed off a fitting and vented all of our air. Otherwise the compressor was able to keep up with our air usage without issue.