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Harrison M300 Issues? Fuse Size?

spitfire_er

Aluminum
Joined
Jul 25, 2014
Location
Minnesota
Harrison M300 Issues? Not working.

Just picked up a 1978 era Harrison M300. I have not been able to get it going. Everything appears to be wired correctly for 230v 3 phase. Running a rotary phase converter.

My main question is there is a small FNM fuse block on the transformer. It currently has a 2.5 amp fuse in it which is what I want to replace. As I was going through the wiring diagram that was with this machine, I saw the fuse and it says "bussmann or equ. .... and 0 5 amp". Can't tell if it's 0.5 or 5 amp. It most likely is 0,5 amp. Assuming that's English for 0.5? It currently has a 2.5 amp fuse and was claimed to be running. The guy I bought it from didn't know left from right.... literally. He tried running it on single phase 220v with a 110-220v transformer. He gave up after he instantly blew the fuse in the purchased transformer.

The above fuse and the power light on the machine are the only two things that I can replace before replacing magnetic switches. Motor is wired correctly too.
 
Last edited:
Multimeter and testing... throwing parts at it is unlikely to help.

Assuming fuse is on the TX secondary? What VA TX? There's your fuse size.

If the fuse is intact it's not the cause of your problems.
 
Says "75VA"... so about .2 amps? I also hauled this thing home over 300 miles and read somewhere that some part or parts can wiggle loose when being hauled. Here is the quoted post

"this type of problem is often caused by mechanical shock during transit which has caused the switch in the starter/contactor overloads to jump out, power off, and try to find the reset button in the starter. Hope this helps"

I have also read that when using a rotary phase converter, they will not work properly if you have L1 or L2 supplied from the generated leg.

may have to look into this.

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I have one rebadged by DoAll of about the same vintage.

Just as a check, make sure there is no issue in the e-stop button circuit. IIRC there is also a safety switch in that circuit that is activated by the geartrain cover. If that is wanky you get no operation either.

Dick


Sent from my iPhone using Tapatalk
 
thanks, I'll have to test across it and see what's going on. To this point I have made sure that everything is in place physically. It was clicking in the panel on and off the other day when I was turning the e-stop on and off. I pulled the fuse, and put it back in and now nothing. I was at least getting the switches clicking before.
 
I started testing tonight. I was able to run the lathe by pressing ether of the magnetic switches which powers the lathe in forward or reverse. All the 240v lines are getting appropriate power.

Starting at the transformer, I followed the exiting wires to the power light, emergency off switch, cover switch and back down to the block. From there I have power leaving wire 4 to the brake switch, but no power back.

I had to quit because I'll have to move the lathe to reach the switch. If I'm lucky maybe a wire came loose.
 
Wasn't the brake switch. Running out of things to test. I'm down to the contractor. Thinking it may be the culprit. Doesn't click on when I power the machine up.
 
Got it figured out. Had a loose #6 wire near the bottom of the panel that looked connected until I basically stuck my face to the ground and looked up at it. That wire powered the contactor. Wire back in place and everything works now as it should.
 








 
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