oldgearhead Senior Member Joined: 25 Jan 2010 Posts: 353 Location: Go Colts! Expertise: I like coffee
Grinder: Virtuoso by Baratza Drip: Chemex,Dilongi DCM900 Roaster: 1/2K Fluid-bed
Posted Sun Oct 28, 2012, 6:16am Subject: Re: Quest M3 Roaster - New Asymmetric Heating?
Endo Said:
>snip<
In any case, the why I look at it, as long as it doesn't break, I'll take what ever extra heat they'll give me. You don't have to use it all, and it certainly seems to help for roasts over 200g.
If so, then what would be the point of the "frigid zone" Quest? I would simply turn up the regular model? No?
To be honest, I'm not clear on this, since I'm also running at higher amps as well (between 9 and 10A mostly), and it seems I could go up to 12A (1400W) if I wanted. (Though I've decided to stay below 1200W for now, until I more clearly understand what's going on in my roaster).
What is the typical amp range and max amps on the regular dual 116v Quest? It says 7.5A to 8.5A in the manual if I'm not mistaken. Can you go much higher?
Dustin360 Senior Member Joined: 17 Feb 2011 Posts: 7 Location: San Francisco, CA Expertise: I live coffee
Posted Sun Oct 28, 2012, 10:35am Subject: Re: Quest M3 Roaster - New Asymmetric Heating?
Mine maxes out at about 11 amps. And ive been preheating the roaster (til 500 met) at max amp/max fan for over 600 roasts. I keep the maximum heat in check though and rarly go above 500(MET). If you dont have an MET reading, maxing the roaster is a craps shoot.
Endo Senior Member Joined: 26 Jun 2008 Posts: 804 Location: , location, location. Expertise: I love coffee
Espresso: machine is < important than... Grinder: !
Posted Sun Oct 28, 2012, 2:08pm Subject: Re: Quest M3 Roaster - New Asymmetric Heating?
Dustin360 Said:
Mine maxes out at about 11 amps. And ive been preheating the roaster (til 500 met) at max amp/max fan for over 600 roasts. I keep the maximum heat in check though and rarly go above 500(MET). If you dont have an MET reading, maxing the roaster is a craps shoot.
I've used a MET for testing as well. (I removed the upper right front cover bolt and installed a wire thermocouple outside the drum).
I noticed my MET goes up to around 270C after my usual 15 minute warmup at 1050W and min fan setting. This seems to be right in line with your 500 (deg F, I assume) MET max. As you can see from the graph, the MET is actually about 75C higher than ET all the way to drop time. (Note: (ET is actually MET in my graph and BT is actually ET inside the drum where since there are no beans during warmup). Of course if you play with the fan or amps, you can easily change this offset (note how the max fan acutally cools the MET by bringing in cold air at 5 min and 8 min marks in my graph....hence the need to always use the fan, as Mr. Yen clearly states).
Another intersting fact; my amps max out at exactly 12.5A (1500W) and at the 50% point on the knob I get about (1000W). In other words, it's not linear. The regular Quest seems to max out at 11A or about 1300W I assume. This is consistant with the fact my Quest needs about 1.5 more amps when roasting.
oldgearhead Senior Member Joined: 25 Jan 2010 Posts: 353 Location: Go Colts! Expertise: I like coffee
Grinder: Virtuoso by Baratza Drip: Chemex,Dilongi DCM900 Roaster: 1/2K Fluid-bed
Posted Sun Oct 28, 2012, 4:58pm Subject: Re: Quest M3 Roaster - New Asymmetric Heating?
What type of circuit is used to control the heaters? Is it: 1) % pulse-type, like sn SSR in manual mode where the output is full on for a % of the time? 2) Mechanical-analog, like a stove-top burner control? 3) Something else?
I think the only way to make comparisons between different Quest roasters is to use watt readings from Kill-A-Watt meters.
Endo Senior Member Joined: 26 Jun 2008 Posts: 804 Location: , location, location. Expertise: I love coffee
Espresso: machine is < important than... Grinder: !
Posted Sun Oct 28, 2012, 5:16pm Subject: Re: Quest M3 Roaster - New Asymmetric Heating?
oldgearhead Said:
What type of circuit is used to control the heaters? Is it: 1) % pulse-type, like sn SSR in manual mode where the output is full on for a % of the time? 2) Mechanical-analog, like a stove-top burner control? 3) Something else?
That's what I'm using. Although I have it on the VA setting (apparent power), not the Watts (real power) with the 0.60 power factor (or whatever it is). I assume others here are comparing VA as well? Are you suggesting we should be using this lower version of Watts (real power) for an accurate comparison? (Funny enough, this is kind of where my problems began, when I was trying to understand which watts reading I should be using. See the link below).
Endo Senior Member Joined: 26 Jun 2008 Posts: 804 Location: , location, location. Expertise: I love coffee
Espresso: machine is < important than... Grinder: !
Posted Sun Nov 4, 2012, 7:10am Subject: Re: Quest M3 Roaster - New Asymmetric Heating?
If I understand this correctly, since my Quest does not operate on a pure resistive circuit like other roasters, and I have a PF of 0.80 due to the triac controller, the real power in watts my heaters are seeing is only 80% of the VA value. In other words, when I'm drawing 10A (as I often do for 200+g roasts), my apparent power (or VA) would be 10A x 120V=1200VA but my real power the heaters see would only be 10A x120V x 0.80=960W (as is indicated on my kill-a-watt when I'm drawing 10A).
This is well below the max wattage rating of 1050W written on the roaster dataplate and well below the combined wattage of 1200W for both heaters.
If so, this would mean I would need to draw roughly 11A to get close to the 1050W max rating. And since my roaster only goes to about 12.5A when dialed all the way up, I need not worry (as Mr.Yen has said numeous times...but without explanation).
Can some electrical person (tech or engineer) confirm this for me?
oldgearhead Senior Member Joined: 25 Jan 2010 Posts: 353 Location: Go Colts! Expertise: I like coffee
Grinder: Virtuoso by Baratza Drip: Chemex,Dilongi DCM900 Roaster: 1/2K Fluid-bed
Posted Sun Nov 4, 2012, 6:16pm Subject: Re: Quest M3 Roaster - New Asymmetric Heating?
Triac? I thought you didn't know how it was controlled? My guess would be a more up-to-date method like'PWM'. In either case I think both the pulse width and the number of pulses in an interval would need to know before a .60 can be assumed.
Most roasters are NOT resistive, but rather SSR controlled. Many SSRs are driven by temperature controllers that use a 10 second pulse. If the controller is set for 80% then the pulse will be on for 8 seconds and off for 2 seconds. A PWM control might use a 90 pulse interval every 10 seconds, then vary the width of every pulse to achive the desired control. Older electric ranges are resistive controlled.
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