How slow can she go?

[Rojo Pedro]

So I bought a Centaur Forge coal forge with an electric blower and propmtly broke the variable speed switch (rheostat). Without thinking I replaced it with the same one. It is obviously not the original switch  

The first thing i noticed in my one short session before I broke the switch was that it produces a xxxx ton of air!  Even at the lowest setting and the air gate mostly closed, it seemed way too much. 

When I got the new switch I noticed the “minimum slow speed adjust” screw and turned it down to the minimumest it would go and now it works a treat. 

My question is thus: how slow can she go? When turned to the lowest speed the motor barely turns (about a quater turn up is about perfect). Will going too slow hurt my motor?  It is a Baldor motor that I assume is ok for variable speed  Applications. 

I dont want to be paranoid but I dont want to damage my baldor either. Thanks in advance for any advice you can spare :-)

[stevomiller]

Sooooo, it’s not a rheostat which is a simple adjustable resistor, your control is solid state so it is a thyristor or triac or some other type of controller. As for your motor being damaged you need to look up the EXACT model number and research it. Contact Baldor even if you are concerned. That’s my advise anywho.

[Rojo Pedro]

Thanks SteveO. 

I wont let it run too awful slow untill i get some more info. 

[ThomasPowers]

Check the motor to see if it's heating up. If it is; then SEEK TECHNICAL ASSISTANCE!  (Before the magic smoke escapes...)  If it's running coal under low load then it will probably be ok. (Also good to check the speed control for excess heat...)

[Rojo Pedro]

Thanks Thomas. I ran it for about 1.5 hours at a mellow forging speed but didnt think to check the temp. Will do so next time

[ThomasPowers]

Basic rule for a lot of electrical stuff---if it's not overheating it's probably OK. (When they had the big aluminum wiring in homes debacle one thing they could do was to do an infrared scan to identify connections that were too warm.)

[stevomiller]

TP gives good advice for checking for imminent danger. Heat @ the motor will mean either it’s loaded to heavily (effective voltage dropped but increased current draw) or the motor isn’t cooling itself, etc. Some motors don’t do well when not run at full speed because their built in fans or other methods aren’t efficient at lower speeds. I definitely follow up with Baldor at some point tho, they’re a premium motor and cooking one would be unfortunate and costly.