The Levers on the Overload relays set the overload trip point.
once the amperage goes through the OL relay a series of bi-metal contacts are made.
when the amperage is too great, the bi-metal contacts separate due to heat distortion and contact is electrically broken at that point.
as the OL contact cools, they will go back to their original positions and electrical contact is once again restored.
those levers just make the OL adjustable for use for different amperage requirements.
the 2 wires that are immersed in oil with wire nuts on them are really making me nervous for you.:bitingnails:
i would address that issue before i attempted hooking up the electricity again.
those wires coming in are large in comparison to the wires they are joined to and may be causing electrical flow issues due to their reduced size, larger wire would not hurt.
oil can be conductive and can cause trouble.
it won't be necessary to do anything with the traversing motor as far as testing at this point.
i'm trying to wrap my head around how they are getting the second speed, for the moment i'm assuming that one contactor is for the main motor, the other contactor is for the traversing motor.
not to try to confuse you but there is machinery that will start in the WYE configuration and RUN in the Delta configuration after the motor is switched to do so, this may be so in your case and would explain the broken fuse. the motor trying to start in the delta configuration was beyond fuse rating
You would start the motor in low speed [WYE 4hp],
then switch to high speed while the motor was powered up,with the High Speed switch on the machine to utilize the Delta configuration [8hp].
there will be a short lag until the windings are re-energized after switching to high speed.
then the motor would get up to full speed again and ready for work.
European motors are sometimes utilized in this method.
kinda like this diagram
or like this
i'm not saying that is 100% the case, but it is worthy of entertainment as a possibility.