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Controller for XU1 motors


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steadfast



Joined: 18 Nov 2009
Posts: 2
Location: Auckland


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Controller for XU1 motors

I've got two motors out of XU1 clone drills that I want to use in my bot at 12V, but I'm unsure what current rating I need in a controller. I've had a read through the info here but no mention I can find of stall current for the XU1.

I see some people are using the IBC and some are using other controllers. The IBC seems a higher spec than I need. Has anyone let the magic smoke out of a controller with these motors and so knows what current rating isn't big enough? I'm thinking the Pololu Trex http://www.pololu.com/catalog/product/777 might be OK? (13A continuous, 30A peak)

By the way, I'm in New Zealand and as there aren't any combat teams here this robot will be non-combat and driven from on-board computer possibly with R/C override, so not quite the same need for raw grunt, but I would like it to be able to climb over bumps and up slopes etc.

Post Sun Nov 22, 2009 7:33 am 
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seanet1310



Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide


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i have an item from pololu that apears to have the same daughter board as the Trex but i wont be able to stress test it for over a month.
This page may be of use to do with the motor drivers in the Trex
http://www.pololu.com/catalog/product/707
I am not sure on the stall current of an xu1 someone else maye be able to help with that or if you have a clamp meter that does DC current you could test it yourself.
Pololu on there forum recomend that stall current of a motor be less then continous current.

An alternative to the IBC that would be about as dificult to interface with would be the scorpion XL and XXL that are both cheeper and have been used to drive drill motors here. (XXL has higher current capability both current limit)

You could also check out the Sabertooth 2x25. It has proven to be anoying for combat robots and specs are a lower then claimed from testign but has driven around a drill motor bot for quite a while but was let in pushing matches. but does have some nice options to interface its avalible at http://www.robotparts.com.au/ who ship to NZ
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Post Sun Nov 22, 2009 9:20 am 
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Valen
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Joined: 07 Jul 2004
Posts: 4436
Location: Sydney


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for non combat use a scorpion will probably suffice, The programming port is open on them as well so you could re-program it to make it easier to interface with.
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Post Sun Nov 22, 2009 10:45 am 
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timmeh
Experienced Roboteer


Joined: 20 Jul 2004
Posts: 2523
Location: Victoria


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scorpion xxl are great esc's not sure how or if you can link em to a pc but they have proven to be tough little controllers and are a good price and they are easy to sell if you didn't need it anymore.
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Post Sun Nov 22, 2009 12:23 pm 
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Andrew W



Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria


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I've found these SyRen controllers http://www.robotmarketplace.com/products/0-SYREN25.html . They are a single channel controller, but can be controlled by serial, analog and RC. I've got 2 of them and I am going to use them in my offroad robot (24V 200w scooter motors, starting with RC and then moving over to serial).

The basic specs are:
Voltage range: 6-24V input nominal, 30V max
Current handling: 25A continuous, 45A peak
Size: 2.4" x 2.3" x 0.8"
Weight: 1.9 oz (55g)
Input types: Analog (i.e. potentiometer), R/C input (radio receiver-no input cable included), or serial (RS-232)
Channels: 1
Synchronous regenerative drive: yes
Ultra-sonic switching frequency: yes
Thermal and overcurrent protection: yes
Lithium protection mode: Yes

Post Sun Nov 22, 2009 2:57 pm 
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Fish_in_a_Barrel



Joined: 30 Sep 2006
Posts: 673
Location: Perth, Western Australia


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Sabertooth knockoff...
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Post Mon Nov 23, 2009 9:38 am 
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Spockie-Tech
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Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia


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Same company
http://www.dimensionengineering.com/

so more likely a model variant than a knockoff Smile
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Post Mon Nov 23, 2009 10:03 am 
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seanet1310



Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide


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a sabertooth is a 2 chanel version of it seams to have same specs so prob same fets
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Post Mon Nov 23, 2009 12:17 pm 
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steadfast



Joined: 18 Nov 2009
Posts: 2
Location: Auckland


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Update

Thanks for all the advice on controllers. I now have the answer to the stall current question.

I put some cash down at Jaycar the other day and came away with a current shunt so I could measure > 10A with my multimeter.

At this point my motors have clutch and chuck as original. I set the clutch to "drill" and clamped the chuck with some vice grips and clamps, hooked up the meter and briefly applied power several times. My multimeter showed various peaks and the highest one I saw was 43A (accompanied by a little smoke). Perhaps if I had a fancier meter with a faster response time and hold I may have seen a higher value for a very short peak. I might also get a higher value once the clutch is properly locked.

I have done an internet search for the motor specs but that model is no longer current, BUT I have just found the piece of paper I wrote down the motor specs on from the internet when I bought it. It says stall current = 60A.

Given my bot is a non-combat bot I probably don't want to push the motor to stall current in order to make everything stay in one piece, so I'm wondering if I should leave the clutch unlocked and have a controller with current limiting, but I guess I should still have a controller rated for at least 45A if not 60A. Sounds like the Dimension Engineering ones won't be up to the task.

Perhaps the IBC is not overkill after all.

Post Sat Nov 28, 2009 9:34 am 
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Rotwang
Experienced Roboteer


Joined: 15 Jun 2004
Posts: 1589
Location: Vic


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Couple of thoughts.
The Sabertooth and Scorpion are current limited so stalling them isn’t normally a problem.
The IBC will provide more pushing power and run higher voltage but is not current or temperature limited.

AFAIK the Sabertooth is not reparable; most times it’s possible to repair the other 2.

I don’t worry about theoretical stall situations, unless a gearbox locks up it can’t normally happen, wheels just spin.

Also max current is limited by batteries and the rest of the circuit wiring, I don’t use heavier wire than necessary, cheap current limiting. Smile

We’ve never damaged a Scorpion using drills, only time weve hurt an IBC on drills is when an overvolted drill threw a wire out of a commentator slot and jammed the motor and shorted the windings.

We have a sabertooth going in a new bot using drills but haven’t used it yet.
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Post Sat Nov 28, 2009 6:15 pm 
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