New Zealand Gold Prospecting & Metal Detecting Forums Archive

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Sparky - Mathematician - Scientist - with abit of commonsence needed

East-Auck-Fossicker		Posted : Sunday, 10 February 2013 8:32:36 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 12/06/2011(UTC) Posts: 84 Location: Auckland Thanks: 10 times Was thanked: 21 time(s) in 11 post(s)		O.K. perhaps the commonsence bit was abit over the top. I brought a Grobet, 15 lb rotary tumbler No 47,780x, last Friday and I'd like to know how much it is costing me to run it 24 - 7 for 3 to 5 weeks to tumble rocks. The specks are, motor, Fusco, type u21, .55A ,50 H2 ( is that the sound ? ) 2500 RPM , 30 HP ( assembled in Mexico ) So who can come up with the longest mathematical story as to how much it is going to cost me to run it 24 -7 ?
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Metal Kiwi		Posted : Sunday, 10 February 2013 9:49:39 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 19/06/2011(UTC) Posts: 1,210 Location: Auckland Thanks: 498 times Was thanked: 484 time(s) in 322 post(s)		Hmmm.... I make it about a 125 watt motor = 0.125 Kilowatts. How much are you charged per Kilowatt hour? Cost per hour x 0.125 x total hours I think will do it. 50 hz is not the sound it is a rating of our AC electricity supply system in NZ which is expressed as 50 cycles per second Alternating Current. If my sums are wrong someone will correct me no doubt. I think your running cost will be quite small. MK
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East-Auck-Fossicker		Posted : Monday, 11 February 2013 4:02:16 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 12/06/2011(UTC) Posts: 84 Location: Auckland Thanks: 10 times Was thanked: 21 time(s) in 11 post(s)		Thanks M K. It works out it will cost me 24.88 cents per 8 hours to run my rock tumbler
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Metal Kiwi		Posted : Monday, 11 February 2013 4:11:01 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 19/06/2011(UTC) Posts: 1,210 Location: Auckland Thanks: 498 times Was thanked: 484 time(s) in 322 post(s)		On that basis it would be about $275.00 per year running 24/7 Hope your drum doesn't flog itself to death in that time. :-) MK
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East-Auck-Fossicker		Posted : Thursday, 14 February 2013 6:19:27 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 12/06/2011(UTC) Posts: 84 Location: Auckland Thanks: 10 times Was thanked: 21 time(s) in 11 post(s)		Talking about how long the machine will last In the instructions , it says to use a light oil once a month on the shafts that the drum rolls on. I used a 30 -40 car oil and after three days the oil had warmed and drained out and the shafts were running dry. So I used grease and it's running fine. So did the manufacturer say to use a really light oil so the machine would wear out and sell you another machine ? It also says in the instructions that the electric motor naturally runs very hot and when it gets too hot it cuts out. So my machine would run for about 10 -15 minutes, cut out for 5 minutes and then start again. There is a little fan disk that was rubbing against the outtercase and stopping the motor. So I carefully pulled it to bits. Ground 3 mm off the fan disk and put it back together. ( you don't think this would affect the warranty do you ?If I touch up a few little scratches on the motor, they will never know. ) I noticed it had no brushes ? Now it runs warm, not hot and doesn't keep stopping. I'am now playing with different appraisives. So if anyone knows what is the best appraisives for a rock tumbler ? I'd love to hear from you.
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gogold		Posted : Thursday, 14 February 2013 7:06:49 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 5/01/2012(UTC) Posts: 217 Location: gore Thanks: 4 times Was thanked: 56 time(s) in 45 post(s)		Originally Posted by: East-Auck-Fossicker Talking about how long the machine will last In the instructions , it says to use a light oil once a month on the shafts that the drum rolls on. I used a 30 -40 car oil and after three days the oil had warmed and drained out and the shafts were running dry. So I used grease and it's running fine. So did the manufacturer say to use a really light oil so the machine would wear out and sell you another machine ? It also says in the instructions that the electric motor naturally runs very hot and when it gets too hot it cuts out. So my machine would run for about 10 -15 minutes, cut out for 5 minutes and then start again. There is a little fan disk that was rubbing against the outtercase and stopping the motor. So I carefully pulled it to bits. Ground 3 mm off the fan disk and put it back together. ( you don't think this would affect the warranty do you ?If I touch up a few little scratches on the motor, they will never know. ) I noticed it had no brushes ? Now it runs warm, not hot and doesn't keep stopping. quote] i think the problem is the the made in china label :)