First off, you'll never ever achieve concentricity by simply drilling a hole in the pulley, no way it'll happen, nor will it control the size of the hole.
The statement is correct in that the motor shaft hole and body must be machined in 1 step. This will offer the best chance for concentricity. But you have to go 1 step further and actually bore the hole, reaming will control the size but will not obtain the best concentricity results. A reamer only follows the path of the existing hole.
I know there are shortcuts and a lot of manufacturers use them because I've seen those results.
IMO, you drill then finish bore the hole for best results so find someone willing to do that and you'll get a nice pulley.
Tapering the hole is an easy way to get a press fit but not good practice in this application, YMMV.
Re: am I too late
Kinda
The specs on the RS website are pretty sketchy but by dividing the no load speed by the voltage we can derive an approximate speed constant of 320 rpm per volt. The torque constant is given as 29 mNm per amp, dividing the speed constant by this gives around 11 rpm / mNm.ohm.
Dividing the no load speed by the stall torque gives us an approximation for the speed / torque slope at about 130 rpm / mNm, divide this by the ratio between the speed and torque constants gives a terminal resistance around 12 ohms.
This motor will work with my drive but not as well as the motor for which it was designed. I also wouldn't use it below 600 rpm.
robbie said:
Kinda
The specs on the RS website are pretty sketchy but by dividing the no load speed by the voltage we can derive an approximate speed constant of 320 rpm per volt. The torque constant is given as 29 mNm per amp, dividing the speed constant by this gives around 11 rpm / mNm.ohm.
Dividing the no load speed by the stall torque gives us an approximation for the speed / torque slope at about 130 rpm / mNm, divide this by the ratio between the speed and torque constants gives a terminal resistance around 12 ohms.
This motor will work with my drive but not as well as the motor for which it was designed. I also wouldn't use it below 600 rpm.
thanks
thanks for the reply Mark.
could I be pointed in the direction of something more suited to the premtech motor.
Thanks
Rob
thanks for the reply Mark.
could I be pointed in the direction of something more suited to the premtech motor.
Thanks
Rob
I have received the second prototype PCBs, built and tested them. I will place orders for all parts tomorrow. Bas, how many confirmed participants do we have?
pcb parts
arad 1 0
Bas Horneman 2 1
zum911 1 1
Lord Dubious 1 1
sklimek 1 0
Kevinchampion 2 2
dod996 2 0
markgall 1 1
Tonyb 1 1
Matt Rowland 1 1
john2 2 1
astro_nut 1 1
Seth Hensel 2 2
DaveM 1 1
Michi124 2 2
Gypsielectro 1 1
Robbie 1 1
superhkm 2 2
Diyfan 1 1
Patriz 10 0
cwise 2 2
werner 2 0
leadbelly 1 0
pcb: 41 parts: 22
Hi Mark,
These have given me their paypal address which I will forward to you. One has confirmed interest but had no paypal account. I asked him to contact you personally.
Cheers,
Bas
arad 1 0
Bas Horneman 2 1
zum911 1 1
Lord Dubious 1 1
sklimek 1 0
Kevinchampion 2 2
dod996 2 0
markgall 1 1
Tonyb 1 1
Matt Rowland 1 1
john2 2 1
astro_nut 1 1
Seth Hensel 2 2
DaveM 1 1
Michi124 2 2
Gypsielectro 1 1
Robbie 1 1
superhkm 2 2
Diyfan 1 1
Patriz 10 0
cwise 2 2
werner 2 0
leadbelly 1 0
pcb: 41 parts: 22
Hi Mark,
These have given me their paypal address which I will forward to you. One has confirmed interest but had no paypal account. I asked him to contact you personally.
Cheers,
Bas
Hi Mark,
I'm the one who won't get another paypal account. (See my April 18 post for explanation.) Can I pay you directly with a US$ money order?
Thanks,
Fred
ps I've tried to contact you directly through various boards and through Quiddity, but with no success.
I'm the one who won't get another paypal account. (See my April 18 post for explanation.) Can I pay you directly with a US$ money order?
Thanks,
Fred
ps I've tried to contact you directly through various boards and through Quiddity, but with no success.
Sorry,
Could I increase my order to 2 sets of boards(4 in total)-please? Spare boards in case of a burn up, or other unforeseen problems.
If I am too late to increase my order-don't worry.
Many thanks.
Could I increase my order to 2 sets of boards(4 in total)-please? Spare boards in case of a burn up, or other unforeseen problems.
If I am too late to increase my order-don't worry.
Many thanks.
OK I have ordered sufficient parts for the orders I have plus two spare. If you're not "on board" yet (sorry) but are still interested, let us know.
I will put the paypals through when I am ready to ship - the board house says 6-8 days but last time it took an extra 6 days to get here.
I vote we all owe Bas something for his efforts in getting this up and running.
I'm not sure about the postal order, they are fairly expensive to cash. How about you contribute $20 to DIYaudio on my behalf and we'll call it quits.
I had you down for one full set (boards and parts). If I read you correctly you now want two sets of boards and one set of parts.
I will put the paypals through when I am ready to ship - the board house says 6-8 days but last time it took an extra 6 days to get here.
I vote we all owe Bas something for his efforts in getting this up and running.
we416b said:
I'm not sure about the postal order, they are fairly expensive to cash. How about you contribute $20 to DIYaudio on my behalf and we'll call it quits.
john2 said:
I had you down for one full set (boards and parts). If I read you correctly you now want two sets of boards and one set of parts.
Sorry, couldn't email Bas only today for 2 PCBs because I was out
on holidays (well, tourist concentration camp + one toddler developing
chickenpox while there) till yesterday.
Do I still have a chance?
1 PCB is fine too. I don't want to eat all spares, if any.
Werner
on holidays (well, tourist concentration camp + one toddler developing
chickenpox while there) till yesterday.
Do I still have a chance?
1 PCB is fine too. I don't want to eat all spares, if any.
Werner
Werner said:
I have increased the order for PCBs so you are in.
I hope your toddler is better - when my son got chickenpox at that age he was so unwell he began hallucinating.
GaryB you are in too.
We have a potential problem in that my supplier for the opa2277 chips doesn't have enough to fill the whole order, delivery will be 3-4 weeks. Mouser, Allied and DigiKey are out too. I'm looking for alternative suppliers other than RS components who want a $3 premium. It might come down to having to pay the premium if you don't want to wait.
Mark,
RE: 'I had you down for one full set (boards and parts). If I read you correctly you now want two sets of boards and one set of parts.'
Yes Please.
RE: 'I had you down for one full set (boards and parts). If I read you correctly you now want two sets of boards and one set of parts.'
Yes Please.
Mark Kelly said:
Mark,
Thanks for letting me jump in at the last minute.
Regarding the OPA2277 - I checked my favorite site for locating parts
http://www.findchips.com/
and they say that the following folks have the opa2277 in stock.
http://www.hrent.com/
They're located in California and I've never bought from them but they might be worth a shot as well. Let me know if you need help contacting them.
Thanks,
---Gary
Mark Kelly said:
Fine. Thanks a lot.
(Sam is fine now, though looking like a horror movie prop)
W
Is this a done deal? Does everyone already have their DC Controller and reated parts? Or is there space for one more late entrant.
GAgola, Nairobi, Kenya
GAgola, Nairobi, Kenya
patriz said:
Yes you are in for 10 boards, no parts. I must say I am wondering - why 10? Friends?
Werner said:
Glad to hear he's OK.
GAgola said:
I am holding one full controller kit and several PCBs as spares in case something goes wrong. I'll put you down for the spare kit which will be available if everything is OK. Motors are being handled by Superhkm and I think Vinyl Addict is looking at making pulleys.
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