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Messages - garymck

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1
AstroEQ Support / Stepper motors-how warm is HOT?
« on: May 26, 2015, 23:02:14 »
Hi Tom,

I have just swapped my stepper motors to some with a lower current requirement as the original ones were causing thermal shutdown despite having large heatsinks attached.

The new ones have the following specs:
Manufacturer Part Number   17HM15-0904S
Motor Type   Bipolar Stepper
Step Angle   0.9°
Holding Torque   36Ncm(50oz.in)
Rated Current/phase   0.9A
Phase Resistance   6.0ohms
Recommended Voltage   12-24V
Inductance   12.0mH±20%(1KHz)

I have set the current limit by measuring vref - set this to .42 volts, so the motors should be limited to a current within their specs. The driver chips barely get warm, however the motors get very warm - not too hot to touch, but about "cup of coffee" warm.... Is this OK? Don't want to damage the motors. Did notice that limiting the current to below the motors specs caused microstepping to become less smooth..

cheers
Gary

2
AstroEQ Support / It Lives !!
« on: May 19, 2015, 01:19:45 »
Hi

Astro EQ arrived and has been set up.

Motors are running smoothly on the bench and slew speed is 1200x (according to the config utility):

Fitted heat sinks to stepper drivers as the steppers pull a bit of current. Will add a fan to them at the weekend.

Losmandy G11
.9 deg steppers
1:1 ratio
360:1 worm.

cheers
Gary




3
Thanks Tom,

order made/paid today
cheers
Gary

4
Hi Tom,

just one quick question before I order.

With a .9 degree stepper using 32 microsteps per full step driving a 360 tooth gear directly, what would the maximum slew speed be?

Aiming for around 600x

Is this possible?

cheers
Gary

5
Hi,

are there any AstroEQ's left for purchase? if so I'd like one!

cheers
Gary

6
DIY AstroEQ / Re: Mega 1280 vs Mega 2560?
« on: April 26, 2015, 08:48:30 »
Thanks,

I found this diagram:

http://astroeq.co.uk/forum/index.php?topic=10.15
post 18 - assume it is correct?

cheers
Gary

7
DIY AstroEQ / Mega 1280 vs Mega 2560?
« on: April 26, 2015, 03:29:39 »
Hi,

basic non electronics person question...

The diagram for the mega connections I think shows the Mega 1280. Are the pin numbers the same as for a Mega 2560?

I have a Mega 2560 and have already managed to load Astroeq onto it, and it responds to Eqmod. I now have to hook up the 8825 stepper boards. Are the pin outs identical?

cheers
Gary

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