Discuss 2 post ramp wiring 3 phase to single phase in the Commercial Electrical Advice area at ElectriciansForums.net

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G

gaz-c

hi, i am in need of some advice on wiring for a 2 post ramp, the ramp is a Bradbury electro mechanical that was 3 phase i have replaced the motor with a 3kw single phase capacitor start capacitor run motor, what i need to know is can i run the motor from the original drum switch and contactors, if so is it a easy set up, i cant post pictures at the moment due to not having enough posts, thanks in advance, Gaz.
 
If you are using the original 3phase contactor, then you would need to link the single phase across all the 3 phases, otherwise the contactor will not pull in correctly.
Connect your feed to the first terminal, link out to the second and on to the third.
Do the same on the out going side.
Failing that, replace the 3phase contactor with a single phase item.
The rotary switch is fine to be used on single phase.
 
Why wont the contactor pull in properly Spin?
Your methods are only needed if an overload is fitted as some require a balanced load across all three lines and motor overload protection could be provided before the contactor in some cases, although it wont do any harm looping single phase through all lines.
 
also check the coil voltage of the contactor. if it's 415V, it will need replacing for one with a 240V coil.
 
Think this really is a case of 'we need to see the wiring plan' as it could be a simple change over or a complicated (if you not up on controls) rewiring of the control system and changing of the control gear, i would have looked at alternative options before replacing the motor personally.
 
More info is required about the ramps method of up and down . Is it hydraulic or pulley and wire .did the motor run opposite direction to take it down or was it by gravity .single phase motors can be wired for forward and reverse .bit more complex than 3 phase but can be done .as a single phase motor would generally have to be much bigger and greedier on amps to give the same starting totque i would recommend altrring the pulley ratio to increase torque and keep the motor size sensible the knock on effect is a slower up speed but its rarely important whether it takes half a minute longer to lift
 
Think this really is a case of 'we need to see the wiring plan' as it could be a simple change over or a complicated (if you not up on controls) rewiring of the control system and changing of the control gear, i would have looked at alternative options before replacing the motor personally.

i have a copy of the original schematics i can scan and upload tomorrow, the reason for going single phase motor was the cost of the inverter £400-£600 and nor guarantee it would work properly
 
More info is required about the ramps method of up and down . Is it hydraulic or pulley and wire .did the motor run opposite direction to take it down or was it by gravity .single phase motors can be wired for forward and reverse .bit more complex than 3 phase but can be done .as a single phase motor would generally have to be much bigger and greedier on amps to give the same starting totque i would recommend altrring the pulley ratio to increase torque and keep the motor size sensible the knock on effect is a slower up speed but its rarely important whether it takes half a minute longer to lift

hi the ramp is a electro mechanical twin screw type with the chain running across the bottom the motor needs to run in both directions to raise it up and down, the motor came with basic wiring diagram.
 
If as you say it is a electro mechanical it may be gravity down, or driven if it is driven it will need to be reversed.
Also take into consideration the extra starting loads when starting with the load off of the floor( IE some way up) If you have changed a 3 hp 3 phase for a single of the same size, this could be a problem.
I have known this to happen particularly when the lift is worn.
The supply cable, protection device( if MCB be changed to a single phase) and isolator, should be checked to ensure they are of sufficient sizes.
The pulley idea is OK you will have to change the belts so you can get the tension right.
Above all don’t get the direction wrong when you first start it, if the arms are on the ground it will unscrew and mess the lift right up.
Always press the down to try it can only go up if wrong.
Another common happening is that when these lifts are moved the chain has to be re tensioned
There is a switch underneath that detects loose or broken chain
 
Last edited by a moderator:
here is the wiring diagram and the picture i hope you can make some sense of them, thanks.

2 post ramp wiring 3 phase to single phase {filename} | ElectriciansForums.net


2 post ramp wiring 3 phase to single phase {filename} | ElectriciansForums.net
 
Its a 400v coil on the contactors, you will need to source either a replacement coil for existing contactors or replace the full contactor assembly on all contactors/relays as i said before there were other methods available to adapt a 400 volt motor to single phase and i would have thought they may have been cheaper in the long run.
 
Its a 400v coil on the contactors, you will need to source either a replacement coil for existing contactors or replace the full contactor assembly on all contactors/relays as i said before there were other methods available to adapt a 400 volt motor to single phase and i would have thought they may have been cheaper in the long run.

Where can you see that?I could be wrong but it looks like its using a single phase to me off terminal 3 on km1?
Probably not much help either way!!!!
 
It's a very old set up Spin. To be honest last time I saw one like it I was an apprentice.
 

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