- Joined
- Jul 27, 2021
- Messages
- 221
I know, I know - I bought a cheap Chinese lathe, but I am not dissatisfied with the machine overall. I am still tuning things up (when I get time) and I expect to have it performing as well as it can pretty soon. This model has a 1100W brushless DC motor and controller on it.
One thing that is odd is related to the power switch and the forward reverse switch. When I power the unit up it comes on and the RPM display and speed pot work fine. If I hit the red button, the display stays on for about 5 or 6 seconds, then flickers with a "tick, tick, tick" sound coming from the controller board. It then shuts off, but the fact that it does this kind of bothers me.
If I have the late on and in the forward position, if I turn the speed down to zero and then switch into reverse it does the same thing as if I had turned if off with the on/off switch. This is annoying as I am fitting an electronic leadscrew to the machine and it has no thread dial (metric leadscrew) and I will be running the leadscrew backwards to move the carriage back without disengaging the half nut.
The direction switch is one of these: https://www.aliexpress.com/item/33006912928.html
The power switch is one of these: https://www.ebay.com/itm/3332428042...z%2BbRFYoKNdGbsICbnc|ampid:PL_CLK|clp:2047675
Assuming the color conventions from the main power inlet to the lathe are correct, the common goes to the rotary switch as well as to the main power switch. Three leads from the direction switch go to the motor controller board and are plugged in there. On the power switch, two of the pins are jumpered together.
I have a couple of questions:
- Is the whole lathe supposed to lose power when in the "0" position in the forward reverse switch? I thought that would just kill power to the motor but leave the rest of the system functioning. I suppose if it just turned off instantly without the delay, ticking sound, and flashing display it might not be an issue, but I would rather not have to open up the little cover and hit the green button every time.
- It seems to me that there is some power discharging somewhere that keeps the display alive for a while - I presume one of the capacitors on the main board. There are two large and a number of smaller ones on there. I noticed that there is a ground wire from the main power that gets sandwiched between the back cover and the main body from one of the panel screws. Both surfaces were painted so I scraped off all the paint thinking that there was no ground to dissipate the cap - no change. My electronics experience is pretty weak so this was just an idea I had for something to try.
- There are no identification markings on this controller board and it has a number of unused connections on it so I am pretty sure this was some excess controller they had laying around so they plopped it into this frankenlathe - the paint color varies in some of the components so I know it was cobbled together from the parts bin. I have half a mind to find a BLDC motor controller and just replace all of this stuff, but would like to see if there is some reasonable fix first.
Anyway, thanks in advance for any information any of you might be willing to share with a newbie machinist.
Tom
One thing that is odd is related to the power switch and the forward reverse switch. When I power the unit up it comes on and the RPM display and speed pot work fine. If I hit the red button, the display stays on for about 5 or 6 seconds, then flickers with a "tick, tick, tick" sound coming from the controller board. It then shuts off, but the fact that it does this kind of bothers me.
If I have the late on and in the forward position, if I turn the speed down to zero and then switch into reverse it does the same thing as if I had turned if off with the on/off switch. This is annoying as I am fitting an electronic leadscrew to the machine and it has no thread dial (metric leadscrew) and I will be running the leadscrew backwards to move the carriage back without disengaging the half nut.
The direction switch is one of these: https://www.aliexpress.com/item/33006912928.html
The power switch is one of these: https://www.ebay.com/itm/3332428042...z%2BbRFYoKNdGbsICbnc|ampid:PL_CLK|clp:2047675
Assuming the color conventions from the main power inlet to the lathe are correct, the common goes to the rotary switch as well as to the main power switch. Three leads from the direction switch go to the motor controller board and are plugged in there. On the power switch, two of the pins are jumpered together.
I have a couple of questions:
- Is the whole lathe supposed to lose power when in the "0" position in the forward reverse switch? I thought that would just kill power to the motor but leave the rest of the system functioning. I suppose if it just turned off instantly without the delay, ticking sound, and flashing display it might not be an issue, but I would rather not have to open up the little cover and hit the green button every time.
- It seems to me that there is some power discharging somewhere that keeps the display alive for a while - I presume one of the capacitors on the main board. There are two large and a number of smaller ones on there. I noticed that there is a ground wire from the main power that gets sandwiched between the back cover and the main body from one of the panel screws. Both surfaces were painted so I scraped off all the paint thinking that there was no ground to dissipate the cap - no change. My electronics experience is pretty weak so this was just an idea I had for something to try.
- There are no identification markings on this controller board and it has a number of unused connections on it so I am pretty sure this was some excess controller they had laying around so they plopped it into this frankenlathe - the paint color varies in some of the components so I know it was cobbled together from the parts bin. I have half a mind to find a BLDC motor controller and just replace all of this stuff, but would like to see if there is some reasonable fix first.
Anyway, thanks in advance for any information any of you might be willing to share with a newbie machinist.
Tom