----- Original Message -----From: JayHSent: Wednesday, March 14, 2012 2:46 PMSubject: [papercreters] MIXERS;It's a lot safer because I can build a completely contained unit that has no power cord to worry about. One can have the batteries in a sealed battery box. All the connections can be run inside sealed areas.
Then roll the mixer, batteries, motor, mixing tank, and all, right up close to the worksite. Configure an isolated on off switching system were the operator never gets close to the electricity, and neither does the water.
I don't see that being done nearly as easily with an AC unit.
The idea of dragging a power cord around through puddles of slurry runoff sounds to me like a death wish.
I think GFI protection is a great invention, but I don't want to count on it as a primary protection for my heart, only as a last resort emergency backup when things go terribly wrong.
spaceman wrote:
Why would you rather use a large DC motor over an AC one? The DC voltage used to drive that motor is as dangerous as the AC and in many cases more so because of higher amperages. Edison was a liar, read Nicola Tesla's work. For over 100 years that particular lie has been in the "common knowledge", that AC is more dangerous than DC. Both require good grounding systems and common sense. Knowledge of electricity is a definite plus.
With a DC motor you can run a low voltage, say 12 volts, but you are going to need large wires to supply the amperage required. Or you can use a higher voltage like 48 with smaller wires and a lower amperage. Basically the same idea with AC motors, you can run 110v, 220v, or even higher. Either way a watt is a watt and it takes close to a thousand of them to make a horsepower. Theoretically 746 but motors aren't 100% efficient, there are hysteresis losses and heat. Anyway, the point is that 5hp worth of DC power supply is not safer than 5hp worth of AC power supply. The energy is the same.
If you keep the motor out of the water and keep the water out of the motor and keep everything nicely bonded and grounded, up to standards, then either can be safe.
My electric barrel mixer has a 1hp 220v motor on it but the blade shaft is bent so it vibrates. I need tuits, too much else going on to fix it right now.
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