96 Powerdrive F300 Getting Started Guide
Issue Number: 5
8.2 Motor thermal protection
A dual time constant thermal model is provided to estimate the motor temperature as a percentage of
its maximum allowed temperature.
The motor thermal protection is modelled using losses in the motor. The losses in the motor are
calculated as a percentage value, so that under these conditions the Motor Protection Accumulator
(04.019) would eventually reach 100 %.
Percentage losses = 100 % x [Load related losses + Iron losses]
Where:
Load related losses = (1 - K
fe
) x (I / (K
1
x I
Rated
))
2
Iron losses = K
fe
x (w / w
Rated
)
1.6
Where:
I = Current Magnitude (04.001)
I
Rated
= Rated Current (05.007)
K
fe
= Rated Iron Losses As Percentage Of Losses (04.039) / 100 %
The Motor Protection Accumulator (04.019) is given by:
Pr 04.019 = Percentage Losses x [(1 - K
2
) (1 - e-
t/τ1
) + K
2
(1 - e-
t/τ2
)]
2. Pr 03.017 = 1, Bandwidth set-up
If bandwidth based set-up is required, the drive can calculate Kp and
Ki if the following parameters are set up correctly:
Pr 03.020 - Required bandwidth,
Pr 03.021 - Required damping factor,
Pr 03.018 - Motor and load inertia.
The drive can be made to measure the motor and load inertia by performing an inertia measurement autotune
(see Autotune Pr 00.040, earlier in this table).
3. Pr 03.017 = 2, Compliance angle set-up
If compliance angle based set-up is required, the drive can calculate Kp and Ki if the following parameters
are set up correctly:
Pr 03.019 - Required compliance angle,
Pr 03.021 - Required damping factor,
Pr 03.018 - Motor and load inertia The drive can be made to measure the motor and load inertia by
performing an inertia measurement autotune (see Autotune Pr 00.040, earlier in this table).
4. Pr 03.017 = 3, Kp gains times 16
If Speed Controller Set-up Method (03.017) = 3 the selected proportional gain used by the drive is multiplied by
16.
5. Pr 03.017 = 4 - 6
If Speed Controller Set-up Method (03.017) is set to a value from 4 to 6 the Speed Controller Proportional Gain
Kp1 (03.010) and Speed Controller Integral Gain Ki1 (03.011) are automatically set up to give the bandwidths
given in the table below and a damping factor of unity. These settings give low, standard or high performance.
6. Pr 03.017 = 7
If Speed Controller Set-up Method (03.017) = 7 then Speed Controller Proportional Gain Kp1 (03.010), Speed
Controller Integral Gain Ki1 (03.011) and Speed Controller Differential Feedback Gain Kd1 (03.012) are set up to
give a closed-loop speed controller response that approximates to a first order system with a transfer function of 1
/ (sτ + 1), where τ= 1/ωbw and ωbw = Bandwidth (03.020). In this case the damping factor is meaningless, and
Damping Factor (03.021) and Compliance Angle (03.019) have no effect.
Pr 03.017 Performance Bandwidth
4 Low 5 Hz
5 Standard 25 Hz
6 High 100 Hz
Powerdrive F300 Getting Started Guide English Iss2.book Page 96 Tuesday, July 28, 2015 3:23 PM
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