Warco WM 16 motor

Same issue with my WM14. After last motor change cut hole in top of motor shroud and added fan as described elsewhere, but also reviewed how I use / load this machine. No problems since.

Do remember these are on HOBBY rated machines with a restricted duty cycle, if you run it too hard it will die.

regards, Mike

There are no field coils to conduct the heat into the motor body !

Field windings add to motor heating, they don't sink it. Most modern industrial DC drives with field controllers have a "field economy" setting that reduces the field current when the motor is at standstill to help reduce heating from this source.

A separate through motor blower will be a big improvement over the built-in "stirrer" and should help to remove heat from the armature - need to allow the warm air an easy escape route, though. Forced air cooling is the way that industrial DC motors get cooled & the (mainly centrifugal) blowers can be very powerful. In most industrial environments, filtration of the cooling air is important & some motors have pressure or airflow sensors to indicate when the filters need changing or cleaning - inadequate airflow leads to burned out field and armature windings.

Just had a 15Kw DC motor rewound from a Correa CNC milling machine at work, though this intitially failed due to a shorted interpole winding, not through an overheating issue - £5500 + Vat & 6 weeks turnaround due to delays getting the correct section wire for the rewind. No real option but a repair this one, as replacements not available any more.

Nigel B.

My WM 16 gets very hot as well, I give it a few hours (or the next day) to cool down and get on with something else. The motor on my budget WARCO bandsaw is even worse. Just one slice with a new blade from a bar of 3" dia. steel reduces the motor to a near meltdown state. Again, I just give it time to cool down before another cut.

As there are no time and motion studies going on in my workshop or targets to aim for I just accept that stuff gets hot and put up with it. After all, if I were to try and hacksaw through a 3" bar of steel I would also get a little warm!

Rik

It sounds like a cooling problem, not an instantaneous power issue.

May I add my vote to cooling fans. It does no good to any part of the motor to cook it.

You may find that it only needs a few more slots, fans are cheap, so they shouldn't be a problem.

fans are cheap, so they shouldn't be a problem.

I agree entirely, but clearly too expensive for them to be supplied as original equipment.🙂

I think its down to warranty claims, not enough customers are burning their motors out.

Obviously a manufacturers fitment needs integrating, filters etc. I can see why they don't bother.

Hi Nigel, Guys,

My comment was aimed at conventional induction motors, having field coils wound on an iron former that directly conducts any heat into the motor body. Since the DC motors used on these mills use ferrite magnets to provide the field and don't generate any heat. Any heat from the armature can only escape via the bearings supporting the armature.

The rather puny fan inside barely moves any air to cool the armature, even at full speed.

No, it's just a fact that the soft plastic gears, as supplied with these Chinese machines, are too soft and don't like high temperature - and as most owners of these mills have found out strip readily.

When working with steel I generally don't take much more than 0.2mm with a milling cutter - and as this isn't generally for exytended periods, there are usually no problems with overheating (anlthough the motor does still get very hot).

The motor has obviously not failed due to overheating but it does start to smell and smoke is visible - this generally happens during fly cutting operations where there is a single point cut over a larger diameter - although I generally don't risk more than around a 0.05mm cut with steel.

I have not removed the "weakest link" from the system. The "upgraded" gears are still the weakest link in the system - although they are now made of engineering nylon PA2200 which has a higher melting point and is much stronger than the soft gray plastic version (which people think is delrin or similar).

The nylon gears have been installed by quite a few users and are definately an improvement - and are also more readily available (and actually cheaper) than trying to get replacements of the stock gears from any of the UK milling machine suppliers.

Something to check is the fan in the motor - that was what actually caused my first motor to melt.

It's just a cheap aluminium blade fan pressed onto the motor shaft. The fan can come loose and slip down the shaft and jam at the bottom of the motor.

The motor will still run as the shaft will quickly wear the pilot hole in the aluminium. If the mill isn't used for extended periods it won't be noticeable (as the fan isn't very efficient in the first place).

I have noticed a big improvement in TBS (time before smoke) by just leaving the top cover off.

Definately a cooling problem.

As I said in another post, there is a marked improvement just by leaving the top cover off.

I've sourced some small fans today and I'm going to try two mounted at the front drawing in and two mounted at the top drawing out.

.

Just curious … does anyone have a specification for this motor ?

MichaelG.

Iain, I found I only needed two fans, mine are mounted at the front of the motor housing and draw air through the slots already in the housing, they pull a fair volume of air through, ample to keep my motor cool. Dave W

There seems to be a few different versions of the top cover for these machines.

Mine only has a small louvre at the back of the top cover.

Same as my WM14 that I posted about earlier - just a small louvre at the back. Always seemed an odd design to me - I suppose it does keep the motor protected from those tiny very sharp shards that go flying about quite often, but still seemed to be ( & eventually proved to be so ) a recipe for overheating even under normal modest use.

Can anyone tell me if the nylon gears are still available somewhere?

The only drive gear I see on ebay at the moment seems to be a very expensive Chinese version at £33.

Try using 'Milling Machine Sacrificial Drive Gear' as a search term - there seems to be a UK seller.

Found them - still on eBay - searching "sacrificial gear" brings up the 3 variations immediately, don't know how that didn't work before?

eBay Item Nos:- 113999695630 (Hi/Lo + Drive), 114231114754 (Drive only) and 114224592712 (Hi/Lo only).

Edited By Peter Bryce on 31/07/2022 08:52:18