the following script

should give you an overview about maintainance and handling of a DC motor.the following information is based on a training carried out together with theBaumueller Service responsible.

1) trouble shooting and sparepart order

iin case of a motor problem, first you will get an Error indication on the Starex, respective onthe Stacotec Computer.

This is usually a general fault indication.In such case do not switch OFF the mainpower, and immediate have a look into the electricalcabinet of the DC-drive.

the Dc-drive will indicate an Error code in showing 159 which is the Fault-code Parameterand followed by one or more code numbers coming in alternating way on the display.

the meaning of each code you can find in the manual for the DC-drive.

KEEP in mind not to switch off the power ! the fault code memory has no backup and will be cleared during power OFF.

FOR any assistance from Starlinger Service you need to let us know the actual Displayinformation on the DC-Controler.

IN CASE any spareparts needed, Starlinger as well as the manufacturer needs to know theserial number of the motor and/or controler.Even, or especially for ordering carbon brushes we need to know the Serialnumber of themotor.

2) motor terminals and thermical-switches

motors of older age are manufactured in insulation class F (150°C)newer motors are specified for insulation class H (170°C)

the used thermicals switches are NC (normaly closed ) and specified to switch OFF 10°Cunder the max. thermical limit of the motor.

>> thermical control for the cooling fan is imortant for the motor, in order to reach the idealworking temperature between 70° and 90°C as fast as possible.Only from 70°C on the particels of the carbon brushes and its additives are able to penetrateinto the collectors surface. This favores to built up the vert antique on the copper, which isnecessary toallow building a film of graphit between brushes and collector, (like greasing)

the surface of the collector reaches under regular working conditionsa temperature between 60° to 95°C.

>> the thermical switches, two of them sitting in thefield winding

he other two sitting in thecommutating winding. Each pair of temp. switches is connected in serial.

90°C u. 170°C

110°C u. 170°C

wide coil: field winding narrow coil: commutating winding

armature winding (7)

Baumueller DC motor

Fan control max temp.switch OFF

carbon brushmicro switches

90°C 110°

170°

170°

3) motor terminalboard

The length of carbon brushes is conroled via micro switches. (NO in serial)This micro switches are riveted to the brush holder ring.From the supplier you only can get the compete ring with all the micro switches as sparepart.

The distance between brush holder and collector =2mmThe bruhes does have a groove for marking the EndUp to this grove the brush may dive into the brush holder ,then the micro switches becomeactiveThis signal will be taken from the PLC and an error message is indicated on the Computerscreen.

After the first warning you should run the motor for maximum 10 to 20 more hours until youchange the brushes.

When running longer than 20 hours you running danger to damage your collector due to theconnecting strip of the brush could already thouch the collector.It gradually will mill then into the surface.

ATTENTION: regular cleaning is very important.

the dust of plastic, remember the working temperatures of up to 95°C, will melt on thebrushes and brushholder and prevent the brushes from easy moving inside the holder.

As a result the contact pressure reduces and causes light sparking

This again causes the brushes to wear earlier and faster, increases the surface temperatureand damages the collector surface like "sand blast"

worse case could also mean the insulation material onte collector to "melt" an change itscircular form to an out of center running.

4) possible electrical checksATTENTION: we strongly recomment not to cary out following on your own.

Pls contact a local motor workshop you can trust to their quality in workmenship

Testing the resistance of field (motor terminal box) most of the motors show the correctresistance on its data plate.Such values are valid for a motor which has reached already working temperature values of a cold motor approximate 30 to 40% below.

The resistance of the armature will be in the range of Mega Ohms.To measure with a standard multimeter does not make sense at all.

Insulation Test should be carried out anyway (1000V test voltage)Such test you always should start in the lowvoltage range (e.g. at 250V and increase then to1000V)

in case of a dirty motor you will earn spark over.

FOR INSULATION TEST ALWAYS DISCONNECT THE MOTOR COMPLETE FROM THEELECTRICAL CABINET

Ground – both field terminalsGround – both armature terminals (only interesting for the connection between terminals andbrushholder)Ground – collector, single lamells

also field – collector

The insulating value for the armature should be 500 – 1000 kOhm with brushes in placewhen brushes out ....MOhms.

for different type of DC motors you can use approx.1kV / Volt armature voltage

insulation value always must be blow 1MOhm

if measured values out of the given tolerances the motor must be cleaned thoroughlydust and oil inside the motor reduces immense.the insulating values of a DC motor.

correct cleaning, see Baumueller motor manual

if the cleaning does not bring up required insulating values so you can expect a defect on the motor.

5) working conditionshousing temperature: up to 80°C

outcoming air from cooling fan (in good working conditions of fan and clean filter)10° to 20°C higher then the ambient temperature is.increased temperature reduces the nominal power of the motornominal details see motor label.

6) how to replace tachometera)remove transparent coverb) remove all 4 pcs brushes carefully, these easy can break.c) in order to remove the rotor of the tachometer you first need to unlook the spring collet by hiting itonce. Then it esyly can be removed by hand from its shaft.Also remove the housing of the tachometer

d) befor installing the new tachometer, ALWAYS CHANGE ROTOR AND HOUSING,check the shaft for perfect centering (center tolerance is 0,02 to max.0,05mm)

The shaft of the tachometer is glued into the motor shaft

WHEN USING AN EXTRACTOR for removing the motorbearing you need to cover the small shaft ofthe tachometer with a small and strong pcs of pipe, on one end closed, which can than be used forthe extractor to put on..

e) for installing and positioning the new rotor use the template which comes along with the newtachometer.This will avoid the rotor to thouch the back of the housing which damages the windings very soon.

f) when fit the brushes back to the tachometer make sure that all 4 pcs perfectly thouchingthe collector surface.

7) carbonbrushes correct handling

replacing carbon brushes, do that right in time according to the groove mark on the brushes,but latest when the micro switches showing an Alarm

when fitting new brushes you always should replace the whole set of brushesNEVER change single brushes, or brushes of different quality.

USE ORIGNINAL BRUSHES ONLY

these will be manufactured from the supplier together with that specific serial of motorin accordiance to the copper used for the collector.Such carbon material is coming in one block of same quality and will kept for later spareneeds. This causes the price to be higher than brushes you can get on the local market.but keep in mind the costs for a defective collector, or in worse case a defective motor.

when new brushes to be fit onto a motor which has already running markings on the collector, so it isinevitable to prepare these brushes bevor use as follows:

first with a file you need to grind the edges and give them a slightly angle

use a pcs of sandpaper, NO, sand or abrasive cloth which you put onto the collector(the cloth on the collector, the sand on the side of brushes)then fit the brushes into its holder and close the spring which presses the brushes onto thecollector.hold the paper and move the motor by hand so that the grooved shape of the collector will betransfered onto the brushes.when finished clean the motor inside from dust properly !!

possible defects caused from incorrect handling

a) early wear of brushesb) early wear and bad rib tread on the collectorc) no built up of vert antique which equals to running a bearing without greased) carbon and collector becomming too hot

could cause mechanical defomation

P.....showes different colours of vert antique on the collector the left half pictures showing perfect to good surface the right half showing mechanical and electrical damages but still can run

B..... showing electrical burn outs

T..... different color view and defective or worn lamells

R.... left pic. regular wear, right pic. doubtful – critical wear.

8) overwork a collector

for grinding the surface of a collector only a lathe or grinding machine should be used with aconcentric running tolerance of 0,03mm

after overworking of the collector the "climate insulation", the insulation material inbetween thecopperlamells must be cut out properly, otherwise the carbon will be milled away immediatly.And this also comes along then with high temperatures to the collector causing already mentionedfaults.

Each copper lamell has a hight of 10 to 12 mm on its Diameter.Depending on the conditions of the collector theoretically it will be possibleto overwork the collector 5 to 7 times which comes to a theoretical lifetime of the motor of 21 years.

ATTENTION: grooves an rib tread does not influence good running conditons as long as enoughdistance between copper and insulating material is still availableAND new brushes will be shaped (grinded befor use)

definitly more critical is an out of center collectoryou can check for such problem when having a look onto the brushes

due to frequently up and down such brushes will be blank on its outside.(worn inside the holder)

critical vibration of the motor is only when this kind of vibration does cause the brushes to lift from thecollector.Vibration could come from dirtor color between frame and motorfoot.

Such situation easily can be checked during regular maintainance can will avoid serious faults.

intensive wear of brushes also could have to do with too low working temperaturewhich avoids the build up of the vert antique (missing grease)

The collector must be free from oil and grease this also avoids the necessary vert antique tobe built.

For cleaning the collector only use a dry and clean clothNever clean, remove the geen color (vert antique) with alcohol or by grinding

9) DC-Motor general points

a) Livetime greased bearings (no lubr.nippels on motor)

does not mean for ever greased !!lifetime equals to approx. 25.000 working hours , equals to 3 to 4 years total lifetime

b) ATTENTION: this is ruled from the bearing greases on the market, and is valid for all lifetimegreased bearings, does not matter which supplier

when overtaking the nominal temperatur of the motor once will reduce the livetime of greasealredy for 50%

c) the motor insulation also is sensitive for overheating ! for the insulation value a temperature overrunof 10°C is already enought to reduce critically its insulation.

d) further negative influences for bearing, motor winding, collector and brushes are:

> excessive humidity > or conductive dust, dirt ( like metallic dust from grinding) penetrate the motor via the cooling fan > corrosive chemicals > intensive vibration!> fume of Silicon (Silikon -> Si-dioxid = sand )

> sparking of carbon brushes damages the collector surface (like sand blasting)after a motor service, when having sparking on the collector check for the correct position ofthe brush holder ring.