GRIT by FEIN GX 75 / GX 75 2H. Sahre / MVK 04 / 2009 Hedenstedt / Grit

Transkript

1 GX 75 / GX 75 2H

2 GX 75 / GX 75 2H Specifications Type GX 75 GX 75 2H Reference number No - load speed (U/min) / 3000 Power input (kw) 3,0 1,5 / 2,0 Voltage (Volt) 3 x x 400 Frequency (Hz) Grinding - belt speed (m/s) / 30 Weight (kg) Class of protection I I Belt dimension (width/lenght in mm) 75 x x 2000

3 Safety precautions Before you start rerpairing and at least after having finished repair ( especially motor or switch ) it s important to test the turning direction of the motor without grinding belt mounted. If the turning direction is wrong (and working with grinding belt mounted) it can cause accidents and damages of the belt grinder. Furthermore you can t adjust a belt grinder correctly if the running direction is wrong! Correct turning direction

4 Test instructions referring to VDE 701 / part 1 Grit belt grinders are basicly placed in protection class 1. After repairing or changing of motor, switch or cable etc. each belt grinder must be electrical tested referring to VDE 701/part 1 as shown in the list below. 1. protective earth conductor test 2. Insulation resistance measurement 1. Activate Measuring points: machine housing against PE on the plug Open circuit voltage on the measuring device: 4 V - 24 V, AC or DC Measurment current: min. 0.2 A Testing time: 3 sec PE resistance: max. 0.3 Ohm with 5 m long mains power cable 1. Activate 2. Connect L1 and N to plug 3. Motor switch "ON" Measuring points: machine housing against L1, L2, L3 Testing time: 3 sec Testing voltage: 500 V DC Insulation resistance: min 2.0 M Ohm 3. High voltage test 1. Activate 2. Connect L1 and N to plug 3. Main switch "ON" Measuring points: Machine against L1, L2, L3 Testing time: 3 sec Testing voltage: 1000 V AC Trip circuit: 5mA > overload relay must not respond

5 Table of contents 1. Drive wheel 1.1. Drive wheel - dismounting 1.2. Drive wheel - mounting 1.3. Adjusting of grinding belt 2. Contact wheel 2.1. Contact wheel - dismounting 3. Gas spring 3.1. Gas spring - dismounting 3.2. Gas spring - mounting 4. Motor 4.1. Motor - dismounting 5. Switch box 5.1. Connection diagrams 5.2. Switch box - dismounting 6. Most common spare parts

6 1. Drive wheel In case of growing noise level or vibrations the Grit Machine must be stopped to check the drive wheel. A new drive wheel is always crowned and balanced. During the grinding process a large volume of grinding dust is produced. This dust can be easily fastened at the inner surfaces (look at picture) of the drive wheel and is causing an unbalance in the drive wheel. Another reason for vibrations can be a broken hub on the inner site of the drive wheel. It can be caused by a failure in the aluminium casting process of the drive wheel. In case of a heavy contamination the drive wheel has to be dismounted and checked from both sides. If necessary the drive wheel has to be changed. A broken hub can t be detected by opening the machine housing. If there are strong vibrations without heavy dust contamination the drive wheel has to be dismounted. Is there a broken hub the drive wheel has to be changed.

7 1. Drive wheel Drive wheel - Aluminium Standard on GX - Machines Drive wheel - Polyurethane Can also be used on GX - Machines, longer endurance as aluminum

8 1. Drive wheel If the grinding belt gets difficult to adjust or steer, you must check the surface of the drive wheel. On a new drive wheel the surface is crowned (left picture). If crowning worn out or if irregular wearing of the surface has occurred the drive wheel must be replaced. Depending on working intensity the endurance is very different. It concerns drive wheels made of aluminiumn as well as drive wheels with polyurethane. The wearing is perceptible when the grinding belt starts moving and it s impossible to steer! New condition crowned surface Normal wear

9 1. Drive wheel The pictures on the left shows an irregular wear out on an unbalanced driving wheel because of a heavy grinding contamination.

10 1.1. Drive wheel - dismounting 1. Open the side door and take it off. 2. Loosen fixing screw/handle of the cover for surface grinding table. 3. Cover for surface grinding table must be taken off. Tool : Allen key 6 mm

11 1.1. Drive wheel - dismounting 1. Loosen the fixing screw of the drive wheel and take it off. 2. Fasten the drive wheel puller onto the drive wheel and screw on the big hexagon head screw using a fork wrench (M24). 3. Take off the drive wheel. Tools : Allen key 8 mm Fork wrench 24 mm Drive wheel puller

12 1.2. Drive wheel - mounting 1. Before the drive wheel is mounted, the shaft must be lubricated. 2. If it s difficult to put the driving wheel on by hand, a rubber mallet can be used to move on the driving wheel with slightly hammer hits. Tools : Rubber mallet

13 1.3. Adjusting of belt tracking

14 1.3. Adjusting of belt tracking In the manual Original

15 2. Contact wheel In case of a noisy and vibrating Grit machine it s also important to check the status of the contact wheel. It is also important to check that the bearings are running noiselees and without any resistance. Vibrations in the contact wheel occur if grinding takes place at the same spot, if the polyurethane lining has come off, if pieces of polyurethane are broken off partly or if the polyurethane has been burnt by red hot dust particles in a full spark box. If the contact wheel runs in a condition as mentioned before, the bearings will fail too. Also the dirt that will be fastened on both sides of the contact wheel during the grinding process can give an unbalance and can damage the bearings if not regularly cleaned.

16 2. Contact wheel In case of changing the ball bearings it s possible to order a service kit that contents the two bearings, different locking rings, distance rings, screws and shaft. Order no.:

17 2. Contact wheel - Loosen nuts - Contact wheel bracket can be moved in 2 directions (forward or backward). A rubber mallet can be very usefull. Last possibility - Read text underneath The contact wheel bracket has been set up from the factory. If it s impossible to adjust the belt, even after replacement of drive wheel, contact wheel or gas spring, it can be necessary to adjust the setting of the contact wheel bracket. However this should only be done as the last possibility after checking all other settings: belt tension, drive wheel, contact wheel and belt adjustment.

18 2.1. Contact wheel - dismounting 1. Loosen handle ( yellow arrow ) 2. Take off spark box with work piece support 3. Take off the eye protection shield.

19 2.1. Contact wheel dismounting 1. Loosen the screw M10 (allen key 8mm) 2. Loosen the screw M8 (allen key 5 mm) 3. Take off the contact wheel Tools : Allen key 8 mm Allen key 5 mm

20 3. Gas spring The gas spring is mainly responsible for the optimal belt tension. A correct belt tension is very important for working with the machine without any problems. If belt tension is to weak the belt will slip on the drive wheel each time the machine is started and switched off even if workpiece is pressed against the belt. This will cause a wear out of the crowning on the drive wheel and creating an unbalance. After a while it will be impossible to hold the belt in the required tracking position. Reduced functioning of a gas spring can be caused by contamination of grinding dust and therefore it is very important clean up the machine regularly ( optimal : every day ) Only an optimal working gas spring guarantees the correct belt tension and the belt change can be done without any problems. Since beginning of 2008 only gas springs from the german company SUSPA are used.

21 3.1. Gas spring dismounting Tools : 1. Loosen the screw with allen key 4 mm. 2. Loosen the nut with fork wrench 13 mm 3. Take off the gas spring. Fork wrench 13 mm Allen key 4 mm

22 3.2. Gas spring - mounting By mounting the gas spring you must be aware of keeping the correct position of the gas spring.

23 4. Motor On GX75 (3 kw) and GX752H (1,5 / 2 kw) two different motors are being used. Due to the fact that the motor is totally sealed the wear of the motor caused by external forces is rather minimal. The most common wear out is detected on the ball bearings. The wear out can happen when the drive wheel is unbalanced (no maintenance on the drive wheel). The risk of a motor failure is minimal and only possible if a failure happens during the winding process or if the motor gets overloaded. In case of worn out of ball bearings it s possible to order a service kit which contents the ball bearings, two rubber seals and a crinkled spring washer. In case of a burnt motor windings the whole motor must be replaced. Standard delivery

24 4. Motor In case of defect ball bearings it is possible to order a service - kit which contents the two ball bearings, a crinkled spring washer and two rubber seals ( look at photo). Order no. is :

25 4.1. Motor - dismounting 1. Loosen and take off the 2 nuts. 2. Remove the 2 metal discs and the motor with the motorflange can be taken off. 3. Loosen and take off the 4 screws in the motorflange and separate the motorflange from the motor. Tools : fork wrench 13 mm allen key 5 mm

26 5. Switch box In case of a defect switch or a defect two speed reverser, the whole switch box included cable and CEE plug must be replaced. Standard delivery GX 75 Standard delivery GX 75 2H

27 5. Switch box In case of a damaged power cable it s possible to get a new power cable with CEE plug as a spare part. Order no. :

28 5.1. Connection diagram GX75 GX75 2H

29 5.2. Switch box - dismounting/gx 75 2H 1. Loosen the 4 screws in the front panel of the switch box and take it off. 2. Loosen the 4 screws in the bottom of the switch box. Tools : Crosshead screw driver PH2

30 5.2. Switch box - dismounting/gx 75 2H 1. Loosen the connection wires from the switch box on the terminal block. 2. Loosen the earth contact where it s connected to the motor housing. 3. Remove the switch box. Tools : Fork wrenh 6 mm Cross head screw driver PH2

31 5.2. Switch box - dismounting/gx 75 2H!!! Important - when disconnecting the wires from the terminal block be aware of the order of the different colours of the wires. Make a note or make a photo!!!

32 6. Most common spare parts Drive wheel, Polyurethane Drive wheel, Aluminium Contact wheel Gas spring Eye protection shield Graphite pad Switch box GX 75 Switch box GX 75 2H Cable with CEE - plug Emergency push button Motor GX 75 Motor GX 75 2H Service kit for contact wheel Service kit for Motor B14 - motorflange Motor shield, ventilator end Ventilator cap for motor Ventilator for motor