Gimson Robotics

**ewan** · 20th March 2013, 17:39

No that's not it, it's for medical research purposes which falls under research grants rather than private investment. As such my name will be on any published papers that may arise from it in future.

**Bodge Job** · 20th March 2013, 18:51

aha nice, and it will be useful when you get old, could use it to chew your food for you!

**ewan** · 15th April 2013, 16:04

In an unconventional fashion I would like to announce that from June 12th all GR02 motors sold will come with an external bearing kit free of charge and a discount offered on shaft mounting hubs. There will also be special rates offered for purchases of four or more motors together. Consider this an incentive to leave off motor orders until after this date if they aren't urgent, something that would help me at the moment, busy as I am!

**ewan** · 28th April 2013, 13:31

24V 550 Motor (Optional) Recall

A number of users have reported manufacturing issues with the 24V 550 motors, in some cases with the motor brushes and on one occasion with the bearings. Unfortunately these are problems that weren't seen during my own testing, indeed they do not affect all of the motors but (it would appear) a large enough proportion that I have decided to offer a recall to anyone who wants it

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The options available for previous motor customers are either

1. Replacement 18V HRS550 motor(s) with a lead/connector option to match that of your original 24V motor purchase. These can be sent within the UK free of charge (possible fee for international shipping) and you will not have to return your 24V motor(s). The motor pinion can be either 9T or 15T

2. A refund of the 24V 550 motor value (£8.90) upon return of each motor

In both cases please contact me directly with your name, original order ID and replacement/refund option if you would like to claim. Also if you have any questions please PM or email me.
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I am hopeful that this will be a more satisfactory resolution than dealing with individual motor problems as they arise. It probably goes without saying that I shan't be using this motor supplier again!

**Liftoff** · 2nd May 2013, 18:29

Hi Ewan, been following the issue with the 24v motors. I bought a couple of motors some time ago which I have not used yet. (I did actually try them out on a power supply to check they work, which they did) I took a closer look at the brushes today as Gary had pointed out the problem seems to crop from this area. It seems the brushes are mounted incorrectly, from the photos it's clear - they seem to be 90 degrees out of phase, and contact with the commutator is just on two points. I noticed when I tried them out that they sparked quite a lot, could have something to do with this?
20130502_20042371191413.jpg 20130502_195805-679075947.jpg

**ewan** · 2nd May 2013, 19:21

Hi Chris. Yes you're correct the brushes have been the cause of most of the problems. For the majority of motors operation has been fine until either heavy loading or impacts which have bought the brush quality issues to light. In most cases the brushes have been visibly fine from a contact and angle perspective but have not handled high operational stresses at all well. Here's a side-by-side view of a set of the 24V brushes by the brushes of a 12V HRS550, spotting the quality differences is not exactly trivial except for those motors which have had a poor contact angle to start with (which may actually include yours by the sounds of it).

IMG_20130502_200001.jpg

Please do email me if you'd like to claim your 18V motor replacements or to send back the 24V motors for a refund as discussed in the previous post. Most previous customers of the 24V motor have now done this.

**Liftoff** · 2nd May 2013, 19:31

Probably it was just a problematic batch, as from your photo both look fine in my eyes. I'll email you Ewan, better not risk using them and swap for the 18v, btw - excellent aftersales Ewan

**Ellis** · 3rd May 2013, 10:57

Agreed. Great service. I'll put a word in to say that the 18v motors are a reliable replacement - they stood up perfectly to 3 fairly hard consecutive events: the champs, Yeovil and then four quite brutal rumbles at Colchester. Any we burned out were purely due to the gearbox issues we experience. Our robot runs hard enough for it to be impossible to keep the wheels tight, and the nature of the weapon is such that it is constantly bucking and bouncing, and the motors are as new. We will be buying more.