Katzhagen - Archive - October 2019
Power to the Krok !
Power pickup improvement
From time to time the Kroks tend to refuse picking up power which at first glance may be blamed on dirty tracks and/or wheels, a bad leveling of tracks or slack contacts inside the drives. In fact, the real crux of the matter is the drives' poor design allowing for power pick up via two wheels per drive and the pickup shoes only. Which is not completely correct since power pickup is limited to three wheels because one is covered by a traction tire. All this results - under accumulating adverse conditions - in a stuttering ride or even a stop.
This complex of problems can be rectified quite easily by using the existing infrastructure for additional carbon brushes:
First the drive units need to be dismounted which requires disassembling the housing and disconnecting the cables.
Both the plows and the compressed air reservoir need to be removed and the crankpins need to be unscrewed from the axles for removing the drive unit.
The rods need to be pulled off the axles and bent away from the frame a bit in order to remove the drive unit.
The unpowered axle's holder can be separated from the drive after loosening the screw as shown in the picture.
A puller is the best choice to remove a wheel from the axle so that it can be removed from its holder. It's easy then to disassemble the holder by removing two screws.
Thanks to the already existing infrastructure it's a simple task to just put in the carbon brushes (short version) which have been wired before and to reassemble the holder.
A small hammer and a 6-8mm aluminum or brass pipe can be used to put back the previously dismounted wheel into its original position.
Re-attach the modified holder and fasten the additional cables with a little self-adhesive tape. The latter eases re-mounting the drive unit.
Before re-attaching the power cable, the new wires have to be soldered to both of the power cable's middle pins. Make sure polarity is correct and connect the power cable to the drive unit again.
Concerns that the additional carbon brushes on the axles not driven by the motor directly may result in early wear of the crankpins and rods are unsubstantiated - given an appropriate lubrication. A related check after having done a 2km test ride showed no signs of any wear of the rods and crankpins.
September 2019 | Archive "Current Affairs" | November 2019
