The SPIKE relay fuse that runs our compressor keeps blowing out when the tank pressure gets up to 120. We’re worried there’s a problem with our compressor. We have checked that it is running with +12V on the red lead and the pressure switch is turning off our compressor (through software) at 120 psi. I just dont get what else may be the problem. Our next fix will be to replace the pump with last years. Any other ideas??
[strike]Check your main robot battery. As the voltage of your main robot battery decreases, the amperage of the current traveling to all your electrical loads will increase. (E.g. Watts = Volts x Amps). This increased amperage is usually what blows the fuse on the Spike relay.
Replacing your main robot battery with a fresh one should take care of most of your issues. ;)[/strike]
Edit: Oops, I forgot Ohm’s Law. :o
Doug,
This occurs due to the high starting current of the pump, up to about 25 amps. The rules state that for the pump Spike only, you may replace the 20 amp fuse with a 20 amp snap action breaker. All should be better.
Art,
Your amps vs. volts would hold true with certain types of power supply but not with the battery. What does occur as the current increases is that the terminal voltage drops. This is due to simple Ohm’s Law V=I*R, for the internal resistance of the battery which is 0.011 ohms. At 100 amps this translates to 1.1 volt drop in the terminal voltage.
Not correct. As the voltage of the battery drops, the current will drop also.
Ohm’s law: current = voltage/resistance. As voltage decreases, current decreases proportionally. (half the voltage, half the current)
As voltage and current decrease, power (watts) decrease dramatically. Thus half the voltage, which results in half the current, means the power is one fourth of what it was.
Is the relief valve installed?
Most of the pressure switches I have seen cut off the compressor at 115 (or less) - if you are actually getting to 120 psi you may not actually be turning off the compressor and it is overloading at 120 and blowing the fuse.
We have the same problem.
So can we use a snap breaker?
Other then avoiding the problem, Is there another way of solving the problem permenently?
thnx,
Barak Shelef
team#2230
Handasaim High-School, Israel.
Barak, at al,
<R65> The control system is provided to allow wireless control of the ROBOTS. The Operator Interface, Robot Controller, speed controllers, relay modules, radio modems, batteries, battery charger, AC adapter, and 9-pin cables can not be tampered with, modified, or adjusted in any way, (tampering includes drilling, cutting, machining, gluing, rewiring, etc.) with the following exceptions:
• Dip switches on the Operator Interface may be set as appropriate.
• User programmable code in the Robot Controller may be customized.
• Speed controllers may be calibrated as described in owner’s manuals.
• The fuse on the Spike relay for the air compressor may be replaced with a 20 Amp Snap-Action circuit breaker.
The last bullet of <R65> is very clear and does solve the problem permanently.
Mike
awesome, our Pneumatics team must have missed that.
Thanks, mike.