Check that the brake is picking fully-grounds on motor or motor wiring-open motor winding-parameter set wrong. If all those are ok then the drive has taken a dump ☹️

Brake switch ok?

sorry, had to ask...!

i was thinking the same thing but didn't want to ask. Scott seems pretty smart and im sure if he's posting here for help he's allready checked it.

I don,t know if you had access to the service tool..if you did you might of found the drive fault.a lot of things can constitute this as well as the conditional status of the brake..its also nice to have roles on your side...like having a expert alongside you in the machine room...

Im almost certain it is the drive, upon further investigation, i would see the lvb board display go blank for a split second, when the problem occurred, then it would come on again, and display check for fault. the 5 and 15 volt supplies on the board never varied. I don't believe that the display should go blank, if a fault occurs. this is the first ovf30 i have encountered, but i believe if a fault occurs the display should not go blank. any way have a drive on order, will keep you posted

If the display goes blank then it could be doing a manual reboot on its own or a bad connection/ power supply. It should not go blank unless you push the reset button or the power is cycled.

check for an open DBR. the display is just switching to the check fault screen it is ok. if the motor was grounded or open or shorted it wont pick the brake. does it do it in both directions, usually a open DBR is directional.

hi green pants, just a question. we picked up a otis 2 sp ac with a ovf mod that wont drive on maintenance. we believe some supterfuge MAY have happened. we went thru the parameters and when you try to drive the drive drops out. all seem ok until you try to drive. is there a parameter that you can turn off or pull a wire that will affect this? normal service works fine. sorry to throw this at you on this thread but i thought it was applicable as we are talking about ovf's.its exactly the same on both lifts.

hmm never seen a 2 speed ac ovf mod but i would guess it is just using one winding in the motor. what controller is it? MCSS, LMCSS or 211? is it running on serial link or discreet wiring to the drive? now im curious.

gidday greenpants. the lift is a genuine otis 2 speed ac with a electronic selector about 20 years old. i would think they wired the drive to the high speed winding. there is an overlay for the drive to replace t and g on the old controllers and thats pretty much it. we took over the service contract and found that maintenance doesnt work on both lifts. in the motorroom the test books state it was tested on handslow and our spies tell us its never worked since installation but we believe its a crock and it MAY have been fiddled with. i think its a ovf 10/20 and i wondered if there was a parameter you can switch off or if a wire you can remove from the drive to stop maintenance to work BUT normal service will operate. when you try to drive the brake relay picks then drops and i think the imputs/outputs to the drive all seem ok.any help would be appreciated.

sounds like a frankenelevator. without prints or seeing it, not sure what i can do.

what is a frankenelevator? you can interogate this drive via the mcs system(although it doesnt prove anything, no faults come up, all we are doing is monitoring the operation). this is why i thought the guys who know the ovf drives well might know of a parameter within the system that was obvious. we still havent really found the fault and suspect a wire may have been removed but with vague prints for the mod its a little hard.

That sounds very familiar...I had a conversation with a friend of mine "in the know". About 2 years ago we discussed a situation were a sales person was trying to sell an OVF drive "mod" onto a 2 speed AC unit. We both came to the conclusion that it was a disaster in the making 😆

e man its a very common mod, which works extremely well designed to eliminate the erratic floor levels of a 2 sp ac lift. there are a truck load of mods like this over here. this here is a 'special case'.