| Understanding
blowers |
Engineers regularly experience problems in running blowers
without breakdown. Sometimes problems are chronic such as frequent
failure of bearings, impellers repeatedly getting imbalanced etc.
In this page we have marked the regular problems
experienced by engineers, possible causes and remedies for the
same.
Problem1: Getting Excessive vibrations repeatedly even after rebalancing & realignment of blower
Possible Causes
- Loose bolts of impeller locking, motor mounting, drive arrangement
- High temperature inside blower causing warpage of impeller material and making it unbalanced.
- Dust, paint, ash deposit on the impeller surface making it unbalanced.
- Weak construction/ wear & tear causing natural vibration
- Impeller colliding with inlet cone.
- Rotating impeller hub/ shaft rubbing with stationery casing.
- Inadequate foundation arrangement. (Unlevel/ Weak Foundation
- Blower running on faulty bearing/ improper bearing fittment
- Loose pulley on shaft.
- Unbalance in pulley.
Problem2: Chronice bearing failures
Possible Cause:
- Improper bearing arrangement selection (by blower manufacturer}
- Inadequate capacity bearing size selection by blower manufacturer
- Improper bearing fittment.
- Pulley loose on shaft
- Wornout shaft/ plummer block
- No expansion clearange for bearing
- High temperature from blower shaft getting transmitted to bearings
- Improper grasing schedule/ improper grease selection
- Flexing in bearing mounting structure (mostly due to weak structure strength)
Problem3: Chronic Motor Tripping/ Failure because of high current
Possible Cause:
- Hig Innertia(starting) load on motor causing motor winding
failure. This can be rectified either by increasing the starting time
(by adjusting relay of starter) or by reducing the impeller weight.
- Unballaced impeller causing motor overload.
- Operating point of blower is changed because of some
changes done in ducting/ removing some resistance (filters/ some
process, equipment causing resistance in air flow is removed).
- Possible increase in blower rpm (by changing pulley/ through vfd) in order to draw more flow out of the blower.
- Impeller hub rubbing at back of casing or intermittently colliding with inlet cone.
Problem4: Blower not giving required flow
Possible Cause:
- Operating point of blower is changed because of some
changes done in ducting/ addinng some resistance (filters/ some process
or equipment causing resistance in air flow is added)
- Intentional/ unintentional reduction in blower rpm
- Leak in ducting
- Some object/ cloth jamed inside ducting giving choking effect.
- Impeller direction of rotation is altered.
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