The AutoMate II acts like an ordinary "infinite control switch" that turns itself up! This is purely a convenience mechanism, which permits the user to set the kiln up, start the firing, and then ignore the process until the scheduled completion time. The AutoMate II starts at zero, and gradually turns up the heat to 100% on during a timing period that the user may set ... from zero to about 10-hours.

When used in combination with an inexpensive shut-off device, such at the "KilnSitter" (W.P.Dawson Inc), a very low cost, fully automated kiln becomes a practical reality!

To keep things simple, the AutoMate II regulates the heating process by establishing a fixed cycle time ... say 30-seconds ... and then adjusting the "on-time"/"off-time" ratio within this timing period. For example, to apply 50% of the heating capacity, the switch turns the heaters on for 15-seconds, and keeps them off for 15-seconds. This method is called "time proportioning" or "duty-cycle proportioning".

As a practical matter, nothing much happens when as the kiln's heating rate is increased from 0% to about 15% ... in other words, this doesn't produce any perceptible temperature rise. Switching the heaters on and off for short little blips in this zone would therefore simply be a waste of mechanical action. The AutoMate II therefore doesn't actually begin the switching process until its output has increased to 10% (approximate).

The initial "dead time" varies directly with the TURN UP TIME setting ... about six-minutes per hour. The "TIMING" light flashes at a rate which is proportional to the turn-up rate, and may be taken as an indication that the AutoMate II is alive and operating properly, even though the "HEATING" light is, as yet, inactive.

(Technically, this reduces the turn-up time by 1/10th of the period you've chosen but, as explained above, since nothing really happens during this initial 10% anyway, this is inconsequential and there's really no reason to compensate for it.)

Turn it on and move the TURN UP TIME knob to the set position. In about ten seconds the HEATING light should blink for the first time. In the SET position, the AutoMate II turns itself up about 10% per second, so each time the HEATING light blinks again, it'll remain on a little longer ... until the tenth time, at which point it should come on and remain on. After several more seconds, the TIMING light should go out, indicating that the switch has gone through its timing period and has turned the kiln full-on.

Each time the HEATING light comes on, you may also hear your heating relay click, or your heaters operating.

Since the AutoMate II uses a dual-primary transformer, you might want to try it with the power cord connected to terminals "B" and "D" to make sure that the second half of the primary is good.

The AutoMate II has earned a reputation that is just the opposite. Very few of these units are returned, and of those that are, only a fraction have bona fide defects in materials or workmanship. Fewer than 10% of the units shipped are ever returned. Of these, some are "false pulls", some are damaged, some have burned-out relay contacts, and some do have circuit failures. The percentages are about evenly split ... 1/4th of the returns in each category.

Some users object to the harmless sparking and "clicking" and "clacking" that these big relays do, and may therefore prefer mercury relays. Technically, mercury relays present a disposal problem and have a potentially "hazardous" failure mode (excessive coil heat sometimes causes the capsule containing the mercury to pressurize and rupture). But when used properly, they can provide reliable service over the life of the kiln.

The solenoid coils of mercury relays tend to be much more highly inductive than those of definite purpose contactors, and might produce erratic operation. If the AutoMate II "chatters", the problem is usually easy to correct by connecting a "snubber" at the contactor's coil connections. Use a .01uf to .1 uF 400v disc or film capacitor connected in series with a 100-ohm 1/2-watt resistor, and connect this network between the coil terminals as shown on the AutoMate II's instruction sheet.

Our production calibration procedure uses a special computer program to select three key component values which optimize the timing accuracy with the TURN UP TIME set at "5" ... so the switch should be most accurate at this setting. Even here, however, the tolerances of practical electronic components usually preclude "exact matches", so the accuracy at this setting may not be perfect.

The TURN UP TIME graduations should be viewed as loosely representing "hours", then used as relative marks as experience proves what the exact timing at a particular setting really is.

The AutoMate II is also much easier to mount than the original model, although this didn't make retrofits easy since it requires that the holes provided in the kiln for the original unit be expanded to a rectangular cut-out for the new unit. A low cost nibbling tool available at your local Radio Shack store can make easy work of this, however.

Part of this is practical and part is philosophical.

Underwriters usually recognize only fixed and settled designs, any significant change or variation in which results in a requirement for reevaluation. The production of low volume, cost sensitive products requires that a high level of flexibility be maintained regarding choices of component types and sources ... a situation that directly conflicts with underwriters' rules. Frequent reinspection forced by such minor issues are simply impractical.

The issue of value is also relevant. Underwriting products involves a significant cost which is, of course, passed on to the buyers of those products. If we choose to involve a third party in our business affairs at a cost to you, we have the ethical and practical obligation to assure that you are receiving some value for that part of the price that represents the cost of their participation.

Everyone has probably observed UL, and perhaps even CSA, stickers on some of the most inexpensive and shoddy electrical merchandise in their local discount store. On inspection, the label will say only that the item is "listed" or "recognized". It does not say "certified" or "approved". It does nothing to really assure quality and safety and, in fact, these organizations specifically disclaim any such inferences.

The underwriting practice has therefore become little more than a marketing game or, in the case of the Canadian CSA requirements, a method primarily designed to favor domestically produced products by creating trade barriers to imports.

AutoMate II units are covered by a 1-year warranty and will be repaired or replaced without charge during this period. When the warranty no longer applies, units are repaired or replaced at a flat-rate charge of US$24.95