amp meter on Performax 16/32 sander

[david brum]

I have an older 16/32 sander which I really like. It can definitely bog down and stall in the middle of a pass however. It does it it I'm trying to take off too much material or if it overheats from long use. Nothing new there. I've found that if I feel the machine beginning to bog down, I can quickly turn down the conveyer speed and the motor won't stall. The newer machines have "smartsand" circuitry which (I think) detects higher amperage draw and turns the conveyer speed down accordingly. I'm thinking that I can permanently attach an amp meter to the motor and perhaps do the same thing manually. Since I don't know a heck of a lot about electricity, I'd love some ideas about what kind of meter to get and how to mount it. For instance, could I get by with an inductive meter, just wrapped around the motor's extension cord?

BTW, a new Jet conveyer motor is $160 and I'm not 100% sure that the circuitry is in the actual motor

Thanks in advance!

[Rod Sheridan]

David, you could install a suitably rated ammeter, pick one that's about 150% of motor rated current.

You could also use a clamp on ammeter however they have to go around one current carrying conductor only. (If you clamp it around the line cord it will read zero because the current is going in opposite directions on the two conductors so the magnetic flux is cancelled).

Regards, Rod

[david brum]

That's good info Rod, thanks very much. I'll shop around a bit for an ammeter and see if there is anything suitable.

[Dan Friedrichs]

As Rod said, you could easily put a clamp-on ammeter onto one of the wires running to the motor. Even something cheap like this would give you a good idea:
http://www.harborfreight.com/digital...ter-95652.html

Something more fancy would be like this:
http://www.diguniverse.com/MARINE-AN...NTS/33953.html

Make sure the one you buy is for AC current, not just DC.

There are 3 different ways for these to sense current - some have a little coil that you slip around one of the motor leads, some have a little "shunt" that you wire in series with one of the motor leads, and some just have 2 terminals on the back (you connect the meter in series with the motor)

[david brum]

Thanks Dan. I also saw a few on online auctions, although I'm confused (like I admitted before, I don't know much about electricity) about why I'd want a DC ammeter, since the sander motor is AC.

Thanks, and I really appreciate the education.

[Dan Friedrichs]

You definitely DON'T want a DC ammeter - make sure it's an AC one.

[Curt Harms]

That's good info Rod, thanks very much. I'll shop around a bit for an ammeter and see if there is anything suitable.

I was looking for the same thing and found an affordable 15 amp direct read ammeter. I figured it wouldn't stand up to the start current surge very well so installed a heavy duty toggle switch. When the toggle switch is in the "start" position it bypasses the ammeter. In "run" position current runs through the ammeter. There may be better solutions but mine works for me. I haven't tripped the overload protection since I installed this setup. The meter was very much like this one except it was 15 amps and I ordered it from a California vendor. A side benefit it that I can plug any 120 volt tool or appliance into this rig and check current draw up to 15 amps.

ebay item # 120609283356

[Curt Harms]

That's good info Rod, thanks very much. I'll shop around a bit for an ammeter and see if there is anything suitable.

I was looking for the same thing and found an affordable 15 amp direct read ammeter. I figured it wouldn't stand up to the start current surge very well so installed a heavy duty toggle switch. When the toggle switch is in the "start" position it bypasses the ammeter. In "run" position current runs through the ammeter. There's a momentary current interruption but I don't notice any change in drum speed at all. I flip the switch before turning the feed conveyor on. There may be better solutions but mine works for me. I haven't tripped the overload protection since I installed this setup. The meter was very much like this one except it was 15 amps and I ordered it from a California vendor.

ebay item # 120609283356
pic1.JPG

pic2.JPG

[david brum]

You definitely DON'T want a DC ammeter - make sure it's an AC one

Thanks Dan, got it. I really appreciate the advice!

[david brum]

I was looking for the same thing and found an affordable 15 amp direct read ammeter. I figured it wouldn't stand up to the start current surge very well so installed a heavy duty toggle switch. When the toggle switch is in the "start" position it bypasses the ammeter. In "run" position current runs through the ammeter. There's a momentary current interruption but I don't notice any change in drum speed at all. I flip the switch before turning the feed conveyor on. There may be better solutions but mine works for me. I haven't tripped the overload protection since I installed this setup. The meter was very much like this one except it was 15 amps and I ordered it from a California vendor.

Thanks Curt. It's great to know that someone has already tried the idea and found that it works. Do you find it difficult to watch the meter while you're feeding and receiving the wood from the sander? Very curious. I really like the way you mounted the meter next to the height gauge.

A few questions:
1)Did you mount it in an electical box?
2)You mentioned that your meter is 15A. Will temporary higher amperage damage the meter?
3)Do you know what amperage kicks off your motor?

Thanks very much. I really appreciate the help and ideas.

[Curt Harms]

Thanks Curt. It's great to know that someone has already tried the idea and found that it works. Do you find it difficult to watch the meter while you're feeding and receiving the wood from the sander? Very curious. I really like the way you mounted the meter next to the height gauge.

A few questions:
1)Did you mount it in an electical box?
2)You mentioned that your meter is 15A. Will temporary higher amperage damage the meter?
3)Do you know what amperage kicks off your motor?

Thanks very much. I really appreciate the help and ideas.

1) I bought a 4" X 4" PVC box. The meter is mounted to the removable front.

2 & 3) I've had the meter peg momentarily a couple times with no damage but it's pretty easy to regulate the conveyor speed to prevent overloads and the feedback is pretty much instantaneous. I don't know what amperage trips the overload, I just know it's irritating.

I'm sure you know this already but a drum sander is not a planer. Light passes are the order of the day.

[Rod Sheridan]

Thanks Curt. It's great to know that someone has already tried the idea and found that it works. Do you find it difficult to watch the meter while you're feeding and receiving the wood from the sander? Very curious. I really like the way you mounted the meter next to the height gauge.

A few questions:
1)Did you mount it in an electical box?
2)You mentioned that your meter is 15A. Will temporary higher amperage damage the meter?
3)Do you know what amperage kicks off your motor?

Thanks very much. I really appreciate the help and ideas.

Hi David, you want to stay below about 100 to 115% of your motor current rating when using the sander with varying work.

If you walk around the sander to pick up a piece, then go to the front and insert a new piece, you'll be fine with the above loading.

If you are going to have a person feeding and a person unloading, the sander will be continuously loaded so you stay at 100% of rating or less.

Check the motor nameplate for the current rating in amperes.

regards, Rod.

[david brum]

Thanks guys. That is enough info for me to move forward. Should be a good way to keep the remaining non-grey hairs I have left.