ROWAN ELETTRONICA S.R.L. - Via Ugo Foscolo, 20 - 36030 CALDOGNO (VICENZA) ITALY
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MAINTENANCE INSTRUCTIONS FOR HIGH SLIP ROWAN MOTORS
“HIGH SLIP ROWAN” type motors are specifically designed to be controlled by tachometrically controlled
electronic circuits and their intrinsic characteristics are especially suited to support repeated start-up surges and
dynamic braking.
Since they are brushless their maintenance is reduced to a bare minimum and normally merely concerns the
bearings and changing the tachometric dynamo, which nevertheless may be necessary after a minimum of 5000
work hours.
Changing bearings or tachometric dynamo
If the motor has to be dismantled to change the bearings, proceed as follows:
1- remove the screws on the rear fan housing or scroll fan and slide it out, disconnecting the wires on the service
terminal block
2- take out the tachometric dynamo
3- slide the stays out and remove the rear housing
4- remove the front housing that comes out followed by the rotor attached to it
5- if necessary remove the front bearing, the dust guard screws and remove the snap ring (if mounted) on the shaft
6- slide the shaft out of the bearing
7- remove the snap ring (if mounted) that holds the bearing on the housing
8- slide off the bearing and replace it with an equivalent type - Z C3 version lubricated with high temperature stringy
grease
9- the rear bearing must be type 2RS C3.
If necessary, replace the tachometric dynamo while assembling the motor.
Calibration of the air gap on the spring or direct brake
If a spring brake is mounted and the air gap requires calibration, proceed as follows:
1- remove the bolts coupling the motor to the brake hub
2- slide off the hub and brake off the shaft
3- remove the screws attaching the brake to the hub,
4- disconnect the brake cable from the terminal block
5- slide the brake off the hub.
At this stage the calibration can be made by adjusting the 3 bolts until an air gap between 0.2 and 0.3mm is
obtained. If the brake mounts a dustproof filter, remove it to access the calibration bolts.
The spring brake is supplied with the maximum braking torque, which can be reduced by unscrewing the specific
crown to a maximum of 40%, always making sure not to unscrew it right out.
If the direct brake has been mounted, there is no need to disassemble it, just control the air gap (maximum 0.3
mm) with a calliper through the side vents and if necessary correct it by slackening the grubscrew on the brake
hub.
Rowan motors require continuous ventilation and therefore it is essential that all the internal and external air
passages in the motor are not blocked by foreign bodies and moreover an adequate air change must be provided.
In particularly aggressive environments Rowan motors, which are normally IP 23, can mount a dustproof filter up
to reach an IP 43 protection rating, and especially in this case frequent controls have to be made to ensure the
filter is clean and the fan is in perfect working order.
Greater protection ratings can be obtained, up to IP 54, providing a completely closed motor down-rated by 50%.
The motor has a heat sensor in the windings that is calibrated to trip at 150°C (Rowan motor windings are class
H with a working temperature limit of 180°C).
The sensor gives a normally closed contact that opens at 150°C and has to be used to cut of the motor power
by a suitable relay switch in the event of an overload. The sensor will take a maximum load of 1A at 230VAC.
If the overload probe trips, check:
- the fan operation
- a free air flow
- the motor absorption, if over the ID plate data, may be caused by excessive load or worn bearings.
