[marsheng]

I need to manually rotate the Z drive. It has a brake on the servo motor. I cant find any details on the electronics of the drive. From the schematics, it looks like it could be 90 volts AC.

[zavateandu]

If you want to manually rotate the Z axis motor and ballscrew ,you have to input from an external power supply voltage to the brake but it is very dangerous as the axis will fall down and must be hold by wood blocks or something to hold it
the driver of the Z axis has nothing to do with the brake voltage control,that is separate controller from the PMC.
In the electrical diagram of the machine you will find the numbers of the wires that can be disconnected from the connectors and mount on the external power supply with a breaker to control the input on/off,quiclky
Good luck

[marsheng]

I am part the way through a full refurbishment and machine is partly disassembled. X and Y are now done. In the mean time , we lost the memory but hopefully have got the right info in the Fanuc OMD.

I turned it on to move the Z into a position to rest it on some wood, but I'm getting error 434 which is the Z axis. As the Z is still to be removed and refurbished I thought I would do it manually. I need to release the brake to turn the ballscrews to get access to the bolts.

From the manual it looks like 90v DC. I thought that was a bit high, hence the posting. Most drives I’ve used are 24v. On the other hand there is no balance weight on the Z and it is heavy, so, maybe the brake is much bigger than expected.

Cant seem to find any Fanuc wiring or specifications for the brakes on these motors.

[zavateandu]

i attached a standard circuit for a brake system in almost any machine,you should see it in your electric book too
the voltage goes from small transformator to a corection bridge and to a realy,in this case you see is KA3
when the PMC conditions are met ,such as EMG OFF and all alrams are off,the KA3 gets energised and the brake gets voltage and free the motor
this is the principle of any brake,controlled by PMC not driver
So,disconnecting the wires from the relay output and put to the external power will do the trick you need.

[servtech]

I am part the way through a full refurbishment and machine is partly disassembled. X and Y are now done. In the mean time , we lost the memory but hopefully have got the right info in the Fanuc OMD.

I turned it on to move the Z into a position to rest it on some wood, but I'm getting error 434 which is the Z axis. As the Z is still to be removed and refurbished I thought I would do it manually. I need to release the brake to turn the ballscrews to get access to the bolts.

From the manual it looks like 90v DC. I thought that was a bit high, hence the posting. Most drives I’ve used are 24v. On the other hand there is no balance weight on the Z and it is heavy, so, maybe the brake is much bigger than expected.

Cant seem to find any Fanuc wiring or specifications for the brakes on these motors.

You will need an external 90vdc power supply, a cheap half wave rectified DC output will be fine for a brake, no need for anything more expensive. 100vdc will be fine too.

Put a plug on the supply side and connect the secondary to the brake. You should hear a "clack" when the brake comes off. Make sure the axis is supported if necessary to prevent it dropping and trapping your hand or damaging the axis.

[marsheng]

Interesting, my wire numbers from a YANG machine are very similar.



I'm away for a few days, but will give it a try when I get back.

[zavateandu]

Interesting, my wire numbers from a YANG machine are very similar.



I'm away for a few days, but will give it a try when I get back.

it is from a YANG SVM 100

[the_gentlegiant]

I manually adjusted my Z axis during a rebuild. It was a very heavy one without any Counterbalance System in place. And yes it is a serious undertaking.

What I did was wired up a stand alone 120VAC Input, 24VDC Output Power Supply through a Foot Switch. (I work alone so needed an extra hand. Also no one would be a quick as me to release the Footswitch should things start going south.) On top of the Spindle Drive was a Timing Pulley that had about a 2 1/2" round Locking Hub on it. I used a carefully played Chain Wrench over that locking hub to control the Ballscrew through the Servo/Timing Belt link. I believe the Servo was electrically disconnected and the machine off. (Not sure it matters.

There was a fair amount of weight present in the feel of the Chain Wrench, though easily manged by the 10-12" length of the wrench handle. Just saying be prepared for some weight. So... hold the wrench up tight, step on the Footswitch, lower or raise maybe one turn, release the Foot Switch, repeat as necessary. I just made sure I wouldn't let the wrench get at an angle where I would loose the tension and hence the lock of the wrench. Slow and safe as they say.

I'm not 100% about this, but I don't believe the brakes are capable of stopping a runaway Z axis column. It may eventually, but it may destroy the brake doing it.

Here's a picture of the column for weight/size reference

[marsheng]

Thanks for the explanation. I'll be doing similar. I'll keep in mind the runaway but hope I never get there.

[servtech]

I manually adjusted my Z axis during a rebuild. It was a very heavy one without any Counterbalance System in place. And yes it is a serious undertaking.

What I did was wired up a stand alone 120VAC Input, 24VDC Output Power Supply through a Foot Switch. (I work alone so needed an extra hand. Also no one would be a quick as me to release the Footswitch should things start going south.) On top of the Spindle Drive was a Timing Pulley that had about a 2 1/2" round Locking Hub on it. I used a carefully played Chain Wrench over that locking hub to control the Ballscrew through the Servo/Timing Belt link. I believe the Servo was electrically disconnected and the machine off. (Not sure it matters.

There was a fair amount of weight present in the feel of the Chain Wrench, though easily manged by the 10-12" length of the wrench handle. Just saying be prepared for some weight. So... hold the wrench up tight, step on the Footswitch, lower or raise maybe one turn, release the Foot Switch, repeat as necessary. I just made sure I wouldn't let the wrench get at an angle where I would loose the tension and hence the lock of the wrench. Slow and safe as they say.

I'm not 100% about this, but I don't believe the brakes are capable of stopping a runaway Z axis column. It may eventually, but it may destroy the brake doing it.

Here's a picture of the column for weight/size reference

Could easy runaway if motor brake is a cone or plate type, serrated tooth plates are much less likely to slip. You can build a second brake between the motor and leadscrew if necessary.