RIP Section 2



"Section 2" is the motor starter for one of the winches on the lifts on Space Probe.

In 1995 the original motors were found to be too small and kept tripping out if a carriage was overweight (whcih happened regularly).

In late 1996 all three winches were (in turn) removed from the hat using a crane, and the motors replaced with larger units.
However the motor controllers (which are down below) were not upgraded, instead the overloads were simply turned up as far as they could go in the hope that it would be enough. It was.. for Lifts 1 and 3.

Lift 2 however continued to trip out and at some stage the overload was removed from #2 to keep it working.

The result soon afterwards was that a section of the 3 phase continuously variable speed controller failed.

It was decided that the reason why the overload kept tripping on that lift wasn't the motor at all but a fault that had been present in the controller since Day 1. The unit remained out of service for many months. They eventually replaced the controller with a new one but there were problems integrating it with the PLC that controls the probe.

They did ultimately get it working but as a result #2 always rose faster than #1 and #3 because the different (newer) inverter controller ramped up the motor start smoother, faster and with more torque than the old original 3 stage SCR ones. The mismatched motor and controller worked fine but there was alot of problems altering the PLC program to accept that one car arrived at the top sooner than the other two. The plan was to replace all three controllers but for some reason this was never done. So in fact towards the end it was #1 and #3 that were the poor cousins, although #2 did occasionally continue to trip it's overload particularly when hot. It was not unusual to see #2 regularly left out of use for this reason as the system was always more reliable when only #1 and #3 were used. For this reason many Park staff probably believed that #2 was stuffed from the beginning.. and thats what the notice reflects. In fact the entire ride was F'd from the beginning as the motors were too small from Day 1. If the motors had been spec'd correctly and the starters thoroughly checked before being put into use none of this would have happened. It's hard to pin blame, but from memory the cost of upgrading the motors was borne by the manufacturer under warranty and not Wonderland. However Wonderland should never have accepted the ride without ensuring the starters were all replaced with the motors, so they're guilty too. It should be noted that really, it was #1 and #3 that were "not working properly". Basically the problem after #2 controller was replaced was that Chair 2 got up the top before #1 and #3. This meant that when #2 arrived, the PLC's safety interlocks interpreted that #1 and #3 had failed and then went into shutdown. To my knowlege the "temporary solution" was to simply fit a few one shot timers to a couple of inputs to the PLC to fool it into thinking that #2 arrived about 1 second after it actually did - which made the system work properly again - most of the time. To compensate an extra limit switch was fitted to #2 to shut down the motor when it reached the top without the PLC's intervention.